Chervenak and McCullough, authors of the most acknowledged ethical framework for maternal–fetal surgery, rely on the ‘ethical–obstetrical’ concept of the fetus as a patient in order to determine what is morally owed to fetuses by both physicians and the women who gestate them in the context of prenatal surgery. In this article, we reconstruct the argumentative structure of their framework and present an internal criticism. First, we analyse the justificatory arguments put forward by the authors regarding the moral status of (...) the fetus qua patient. Second, we discuss the internal coherence and consistency of the moral obligations those authors derive from that concept. We claim that some of the dilemmas their approach is purported to avoid, such as the debate about the independent moral status of the fetus, and the foundation of the moral obligations of pregnant women (towards the fetuses they gestate) are not, all things considered, avoided. Chervenak and McCullough construct the obligations of physicians as obligations towards entities with equal moral status. But, at the same time, they assume that the woman has an independent moral status while the moral status of the fetus is dependent on the decision of the woman to present it to a physician for care. According to the logic of their own argumentation, Chervenak and McCullough implicitly admit a different moral status of the woman and the fetus, which will lead to different ascription of duties of the physician than those they ascribed. (shrink)

This article focuses on maternal-fetal surgery (MFS) and on the concept of clinical equipoise that is a widely accepted requirement for conducting randomized controlled trials (RCT). There are at least three reasons why equipoise is unsuitable for MFS. First, the concept is based on a misconception about the nature of clinical research and the status of research subjects. Second, given that it is not clear who the research subject/s in MFS is/are, if clinical equipoise is to be used as a (...) criterion to test the ethical appropriateness of RCT, its meaning should be unambiguous. Third, because of the multidisciplinary character of MFS, it is not clear who should be in equipoise. As a result, we lack an adequate criterion for the ethical review of MFS protocols. In our account, which is based on Chervenak and McCullough's seminal work in the field of obstetric ethics, equipoise is abandoned. and RCT involving MFS can be ethically initiated when a multidisciplinary ethics review board (ERB), having an evidence-based assessment of the risks involved, is convinced that the value of answering the research hypothesis, for the sake of the health interests of future pregnant women carrying fetuses with certain congenital birth defects, justifies the actual risks research participants might suffer within a set limit of low/manageable. (shrink)

Ordo II comprises the work that made Erasmus famous, namely the Adagia some of which were extended into essays. This first volume of the Adages in the Amsterdam edition of the Latin texts of Erasmus gives a general introduction to the Adages in German, as well as a critical edition of the Latin text of the first half of the first thousand Adages.

The second volume of the Adagia of the Amsterdam edition of the Latin texts of Erasmus gives an introduction in German and a critical edition of the Latin text of the second half of the first thousand Adages.

Part Five of the Amsterdam edition of the Latin text of Erasmus’ Annotations to the New Testament presents his notes on Paul’s letters to the Galatians, Ephesians, Philippians, Colossians, and to the Thessalonians 1 & 2.

Part Four of the Amsterdam edition of the Latin text of Erasmus’ Annotations to the New Testament presents his notes on St. Paul’s letters to the Corinthians.

The ninth and last volume of the Adagia of the Amsterdam edition of the Latin texts of Erasmus gives an introduction in German and a critical edition of the Latin text of the Collectanea , an early version of the Adagia that completely differs from the latter collection.

Background: Debates over legalisation of physician-assisted suicide or euthanasia often warn of a “slippery slope”, predicting abuse of people in vulnerable groups. To assess this concern, the authors examined data from Oregon and the Netherlands, the two principal jurisdictions in which physician-assisted dying is legal and data have been collected over a substantial period.Methods: The data from Oregon comprised all annual and cumulative Department of Human Services reports 1998–2006 and three independent studies; the data from the Netherlands comprised all four (...) government-commissioned nationwide studies of end-of-life decision making and specialised studies. Evidence of any disproportionate impact on 10 groups of potentially vulnerable patients was sought.Results: Rates of assisted dying in Oregon and in the Netherlands showed no evidence of heightened risk for the elderly, women, the uninsured , people with low educational status, the poor, the physically disabled or chronically ill, minors, people with psychiatric illnesses including depression, or racial or ethnic minorities, compared with background populations. The only group with a heightened risk was people with AIDS. While extralegal cases were not the focus of this study, none have been uncovered in Oregon; among extralegal cases in the Netherlands, there was no evidence of higher rates in vulnerable groups.Conclusions: Where assisted dying is already legal, there is no current evidence for the claim that legalised PAS or euthanasia will have disproportionate impact on patients in vulnerable groups. Those who received physician-assisted dying in the jurisdictions studied appeared to enjoy comparative social, economic, educational, professional and other privileges. (shrink)

Precision medicine research involving human biological material is becoming an increasingly central component of healthcare, and its potential is quickly growing due to rapid technological progress...

Although Next Generation Sequencing (NGS) has increased our ability to test and diagnose, its results are often not clear-cut and require a complex interpretation and negotiation process by both healthcare professionals and patients involved. In this paper, we explore how diagnoses identified through NGS are socially shaped under influence of the broader social context. Using an analytical framework stemming from the sociology of health and illness and science and technology studies, with a focus on the construction of diagnosis and the (...) role of uncertainty in medicine, we analyze the existing corpus of literature on NGS diagnostic practices. We show how in this early implementation phase of NGS, in which standardization efforts are not yet solidified, the boundary struggles around diagnoses obtained through NGS are particularly visible. We discuss the different steps in the diagnosis shaping process and what it subsequently entails to give and a receive a diagnosis using NGS. (shrink)

Given its non-invasive nature, there is increasing interest in the use of transcutaneous vagus nerve stimulation across basic, translational and clinical research. Contemporaneously, tVNS can be achieved by stimulating either the auricular branch or the cervical bundle of the vagus nerve, referred to as transcutaneous auricular vagus nerve stimulation and transcutaneous cervical VNS, respectively. In order to advance the field in a systematic manner, studies using these technologies need to adequately report sufficient methodological detail to enable comparison of results between (...) studies, replication of studies, as well as enhancing study participant safety. We systematically reviewed the existing tVNS literature to evaluate current reporting practices. Based on this review, and consensus among participating authors, we propose a set of minimal reporting items to guide future tVNS studies. The suggested items address specific technical aspects of the device and stimulation parameters. We also cover general recommendations including inclusion and exclusion criteria for participants, outcome parameters and the detailed reporting of side effects. Furthermore, we review strategies used to identify the optimal stimulation parameters for a given research setting and summarize ongoing developments in animal research with potential implications for the application of tVNS in humans. Finally, we discuss the potential of tVNS in future research as well as the associated challenges across several disciplines in research and clinical practice. (shrink)

Given its non-invasive nature, there is increasing interest in the use of transcutaneous vagus nerve stimulation across basic, translational and clinical research. Contemporaneously, tVNS can be achieved by stimulating either the auricular branch or the cervical bundle of the vagus nerve, referred to as transcutaneous auricular vagus nerve stimulation and transcutaneous cervical VNS, respectively. In order to advance the field in a systematic manner, studies using these technologies need to adequately report sufficient methodological detail to enable comparison of results between (...) studies, replication of studies, as well as enhancing study participant safety. We systematically reviewed the existing tVNS literature to evaluate current reporting practices. Based on this review, and consensus among participating authors, we propose a set of minimal reporting items to guide future tVNS studies. The suggested items address specific technical aspects of the device and stimulation parameters. We also cover general recommendations including inclusion and exclusion criteria for participants, outcome parameters and the detailed reporting of side effects. Furthermore, we review strategies used to identify the optimal stimulation parameters for a given research setting and summarize ongoing developments in animal research with potential implications for the application of tVNS in humans. Finally, we discuss the potential of tVNS in future research as well as the associated challenges across several disciplines in research and clinical practice. (shrink)

Recent policy developments in the area of livestock husbandry have suggested that, from the perspective of optimizing animal welfare, new animal husbandry systems should be developed that provide opportunities for livestock animals to be raised in environments where they are permitted to engage in “natural behavior.” It is not known whether consumers regard animal husbandry issues as important, and whether they differentiate between animal husbandry and other animal welfare issues. The responsibility for the development of such systems is allocated jointly (...) between farmers, regulators, different actors in the food chain, and consumers. This research focuses on understanding consumer attitudes and preferences regarding the development and introduction of such systems, to ensure that they are acceptable to consumers as well as producers, regulators, and scientists. Consumer perceptions of animal welfare and animal husbandry practices were evaluated using quantitative consumer survey, which focused on two animal husbandry issues – farmed pigs and farmed fish. Following pilot work, 1000 representative Dutch consumers were sampled about their attitudes to either pig or fish husbandry. The results indicated that consumers think about animal welfare in terms of two broad categories related to their health and living environment, but do not think about welfare issues at a more detailed level. Greater concern was expressed about the welfare of pigs compared to fish. Consumer trust in labeling also emerged as an important issue, since consumers need to trust different food chain actors with responsibility for promoting animal welfare, and are reluctant to consider the details of animal husbandry systems. As a consequence, a transparent, enforceable, and traceable monitoring system for animal welfare friendly products is likely to be important for consumers. (shrink)

ObjectivesMany older adults with visual impairment also have significant hearing loss. The aim was to investigate the effectiveness of a newly developed Dual Sensory Loss protocol on communication and wellbeing of older persons with DSL and their communication partners in the Netherlands and Belgium.MethodsParticipants and their communication partners were randomized in the “DSL-protocol” intervention group or a waiting-list control group. The intervention took 3 to 5 weeks. Occupational therapists focused on optimal use of hearing aids, home-environment modifications and effective communication (...) strategies. The primary outcome was the Communication Strategies domain of the Communication Profile for the Hearing Impaired. Secondary outcomes measured in participants were the Low Vision Quality Of Life Adjustment subscale, the Center for Epidemiological Studies - Depression Scale, De Jong Gierveld Loneliness Scale and the Fatigue Assessment Scale. The Hearing Handicap and Disability Inventory - Reaction of Others subscale and the Care-related Quality of Life - 7 Dimensions was measured in communication partners. Measurements were taken at baseline and 3-month follow-up. Linear mixed models were used to analyze effects between groups over time for every outcome measure.ResultsIntention-to-treat analyses showed a significant effect of the DSL-protocol on the use of verbal strategies in favor of the control group, however, this effect was non-significant after adjustment for confounding. Effect sizes of other outcomes varied between −0.23 [−0.57, 0.12] and 0.30 [−0.05, 0.64]. The LMM showed a significant effect on the HHDI-Reaction of others scale in favor of communication partners in the treatment group, however, the effect did not remain significant at a 0.01 significance level and the effect size was very small and non-significant 0.12, 95% CI [−0.27 to 0.51]. Adjusted analyses did not reveal treatment effects.ConclusionThe DSL-protocol did not clearly contribute to the enhancement of communication and wellbeing in DSL-patients. Possible reasons for the lack of effects are OTs not being comfortable giving advice on communication and psychosocial issues or the short-term treatment and follow-up period. Further study is warranted to find out how the protocol may be adapted or whether it is necessary to involve mental healthcare professionals.Clinical Trial Registrationwww.ClinicalTrials.gov, identifier NTR2843. (shrink)

Moral sensitivity and moral reasoning are essential competencies biomedical researchers have to develop to make ethical decisions in their daily practices. Previous research has shown that these competencies can be developed through ethics education. However, it is unclear which underlying mechanisms best support the development of these competencies. In this article we argue that the development of moral sensitivity and moral reasoning can be fostered through teaching strategies that tap into students’ moral imagination. We describe how moral imagination can stimulate (...) the development of these competencies through three different merits of moral imagination. Moral imagination can help students to 1) transfer and apply abstract moral concepts to concrete situations and contexts, 2) explore the perspective of others, 3) explore and foresee the moral consequences of different decisions and actions. We explain these three merits of moral imagination in the context of biomedical research and present a theoretical model for how these merits can be used to stimulate the development of moral sensitivity and moral reasoning. Furthermore, we describe multiple teaching strategies for biomedical curricula that tap into the three merits of moral imagination. These teaching strategies can inspire teachers to design ethics education that activates students’ moral imagination for the development of moral sensitivity and moral reasoning. (shrink)

OBJECTIVES: To determine the relationship between ethical reasoning and gender and occupation among a group of male and female nurses and doctors. DESIGN: Partialist and impartialist forms of ethical reasoning were defined and singled out as being central to the difference between what is known as the "care" moral orientation (Gilligan) and the "justice" orientation (Kohlberg). A structured questionnaire based on four hypothetical moral dilemmas involving combinations of (health care) professional, non-professional, life-threatening and non-life-threatening situations, was piloted and then mailed (...) to a randomly selected sample of doctors and nurses. SETTING: 400 doctors from Victoria, and 200 doctors and 400 nurses from New South Wales. RESULTS: 178 doctors and 122 nurses returned completed questionnaires. 115 doctors were male, 61 female; 50 nurses were male and 72 were female. It was hypothesised that there would be an association between feminine subjects and partialist reasoning and masculine subjects and impartialist reasoning. It was also hypothesised that nurses would adopt a partialist approach to reasoning and doctors an impartialist approach. No relationship between any of these variables was observed. (shrink)

With a large number of forcibly displaced people seeking safety, the EU is facing a challenge in maintaining solidarity. Europe has seen millions of asylum seekers crossing European borders, the largest number of asylum seekers since the second world war. Endemic diseases and often failing health systems in their countries of origin, and arduous conditions during transit, raise questions around how to meet the health needs of this vulnerable population on arrival in terms of screening, vaccination, and access to timely (...) and appropriate statutory health services. This paper explores the potential role of the principle of reciprocity, defined as the disposition ‘to return good in proportion to the good we receive, and to make reparations for the harm we have done’, as a mid-level principle in infectious disease screening policies. More than half of the European countries implemented screening programmes for newly arrived asylum seekers. Screening may serve to avoid potential infectious disease risks in the receiving countries as well as help identify health needs of asylum seekers. But screening may infringe upon basic rights of those screened, thus creating an ethical dilemma. The use of the principle of reciprocity can contribute to the identification of potential improvements for current screening programmes and emphasizes the importance of certain rights into guidelines for screening. It may create a two way moral obligation, upon asylum seekers to actively participate in the programme, and upon authorities to reciprocate the asylum seekers’ participation and the benefits for the control of public health. The authors argue that the reciprocity principle leads to a stronger ethical justification of screening programmes and help achieve a balance between justifiable rights claims of the host population and the asylum seekers. The principle deserves a further and more thorough exploration of its potential use in the field of screening, migration and infectious diseases. (shrink)

Using telephone interviews among a random sample of 537 Dutch children aged 7–12 years old, we investigated the prevalence of fear reactions to television news among younger and older children and among boys and girls, what types of news items children in different age and gender groups refer to as frightening, and whether children's fear reactions to regular adult television news differed from their fear reactions to a special children's news program. Overall, 48.2 % of the children who reported watching (...) the adult or children's news programs, reported fear reactions to adult news, while 32.6 % reported fear of children's news content. For both types of news programs, younger children and girls more often reported fear than older children and boys did. The most prevalent fear-inducing news content categories were interpersonal violence, fires, accidents, and disasters, and visual depictions of the consequences of violence. (shrink)

Patient-reported outcomes are frequently used for medical decision making, at the levels of both individual patient care and healthcare policy. Evidence increasingly shows that PROs may be influenced by patients’ response shifts and dispositions. We identify how response shifts and dispositions may influence medical decisions on both the levels of individual patient care and health policy. We provide examples of these influences and analyse the consequences from the perspectives of ethical principles and theories of just distribution. If influences of response (...) shift and disposition on PROs and consequently medical decision making are not considered, patients may not receive optimal treatment and health insurance packages may include treatments that are not the most effective or cost-effective. We call on healthcare practitioners, researchers, policy makers, health insurers, and other stakeholders to critically reflect on why and how such patient reports are used. (shrink)

PurposeAlthough an increasing body of literature suggests a relationship between brain irradiation and deterioration of neurocognitive function, it remains as the standard therapeutic and prophylactic modality in patients with brain tumors. This review was aimed to abstract and evaluate the prediction models for radiation-induced neurocognitive decline in patients with primary or secondary brain tumors.MethodsMEDLINE was searched on October 31, 2021 for publications containing relevant truncation and MeSH terms related to “radiotherapy,” “brain,” “prediction model,” and “neurocognitive impairments.” Risk of bias was (...) assessed using the Prediction model Risk Of Bias ASsessment Tool.ResultsOf 3,580 studies reviewed, 23 prediction models were identified. Age, tumor location, education level, baseline neurocognitive score, and radiation dose to the hippocampus were the most common predictors in the models. The Hopkins verbal learning and the trail making tests were the most frequent outcome assessment tools. All studies used regression as machine learning method. All models were judged to have a high risk of bias mainly due to issues in the analysis.ConclusionExisting models have limited quality and are at high risk of bias. Following recommendations are outlined in this review to improve future models: developing cognitive assessment instruments taking into account the peculiar traits of the different brain tumors and radiation modalities; adherence to model development and validation guidelines; careful choice of candidate predictors according to the literature and domain expert consensus; and considering radiation dose to brain substructures as they can provide important information on specific neurocognitive impairments. (shrink)

BackgroundIn research ethics, the most basic question would always be, “which is an ethical issue, which is not?” Interestingly, depending on which ethics guideline we consult, we may have various answers to this question. Though we already have several international ethics guidelines for biomedical research involving human participants, ironically, we do not have a harmonized document which tells us what these various guidelines say and shows us the areas of consensus. In this manuscript, we attempted to do just that.MethodsWe extracted (...) the imperatives from five internationally-known ethics guidelines and took note where the imperatives came from. In doing so, we gathered data on how many guidelines support a specific imperative.ResultsWe found that there is no consensus on the majority of the imperatives and that in only 8.2 % of the imperatives were there at least moderate consensus. Of the 12 clusters, Informed Consent has the highest level of consensus and Research Collaboration and Regulatory Sanctions have the least.ConclusionThere was a lack of consensus in the majority of imperatives from the five internationally-known ethics guidelines. This may be partly explained by the differences among the guidelines in terms of their levels of specification as well as conceptual/ideological differences. (shrink)

Résumé : Le PPBS a été conçu comme un instrument destiné à ceux qui décident de l'allocation des ressources publiques : il doit leur permettre de prendre de meilleures décisions. S'il est très difficile de repérer et de juger les choix que le développement du système a inspirés aux Etats-Unis, il n'en est pas mains certain que ses résultats tangibles sant maigres car la masse des anciens programmes, principale source potentielle de moyens nouveaux, n'a guère été remise en question.La valeur (...) intrinsèque du PPBS ne peut être mise en cause. Ce qui doit l'être, c'est la lenteur de son développement, qui demeure peu avancé. Cette lenteur s'explique, car le système ne peut produire des fruits dans une terre stérile qu'on n'a pas préparée.La brutalité et les maladresses de l'opération déclenchée en 1965 dans le gouvernement fédéral américain ne pouvaient que renforcer la résistance au changement et retarder, sinon compromettre, le succès final. Les perspectives demeurent heureusement favorables, puisque la nouvelle administration ne semble pas décidée à faire machine arrière et que les Etats et Villes ont démarré sous de bien meilleurs auspices.La principale conclusion qu'imposent les expériences américaines est que toute juridiction intéressée par le PPBS doit impérativement développer, de la façon la plus générale, la volonté d'instaurer le système et s'assurer les moyens de le faire. C'est dire qu'il est peu sage d'engager la bataille sur tous les fronts à la fois : il faut tenter des percées. Mais c'est dire aussi combi en l'information et la formation sant essentielles. A cet égard, l'installation généralisée de certains éléments du système, à savoir la structure de programmes et le budget-programme, loin de présenter des inconvénients, peut constituer un excellent exercice en dehors de son utilité directe pour le preneur de décision. La bataille en cause est surtout celle de la conviction: l'outil est prêt, il est bon, encore faut-il que l' ouvrier accepte de s'en servir.Samenvatting:Planning-programming-budgeting werd ontworpen als een instrument voor diegenen die beslissen over de toewijzing van de overheidsmiddelen.Dit instrument moet de beslissers in staat stellen betere beslissingen te treffen. Het is niet makkelijk deze beslissingen op te sporen en te beoordelen welke in de Verenigde Staten getroffen werden onder invloed van de ontwikkeling van deze systeembenadering. Toch is het met vrij grote zekerheid te stellen dat de tastbare resultaten gering zijn omdat de veelheid aan oude programma's die tenslotte toch de voornaamste potentiële bronnen zijn van nieuwe middelen, nooit werden aangevochten.De intrinsieke waarde van PPBS kan daarom evenwel niet worden genegeerd. Wat wel dient aangeklaagd is de traagheid van zijn aanslepende ontwikkeling. Deze traagheid is te verklaren door het feit dat het systeem slechts vruchten kan afwerpen zo het ingeplant wordt in degelijk voorbereid terrein.De brutaliteit en de onhandigheden bij de operatie die in 1965 werd ingezet in het amerikaans federaal overheidsbestel konden niets anders dan de weerstand tegen de verandering versterken en afbreuk doen aan het uiteindelijk slagen van het systeem. Gelukkiglijk blijven de vooruitzichten gunstig want de nieuwe beleidsvoerders sinds de presidentsverkiezingen, blijken ermee te willen doorgaan en de staten en lokale overheden zijn ermee van wal gestoken onder veel betere omstandigheden. Het doorslaggevend besluit uit de amerikaanse ervaringen terzake is wel dat elke instantie welke belangstelling heeft voor PPBS, nodig moet op zo breed mogelijk vlak de wil doen groeien om het systeem te ontwikkelen en er ook de nodige middelen toe ter beschikking stellen. Dit betekent tevens dat het weinig aan te bevelen is de strijd op alle fronten terzelvertijd aan te binden maar wel geleidelijk doorbraken te verwezenlijken. Dit brengt dan evenwel ook met zich dat informatie en vorming essentieel zijn bij deze strategie. In dit verband moet dan ook gezegd worden dat reeds het invoeren van sommige deelementen van het systeem, zoals de programmastructuur en het programmabudget, voor de beslisser nuttig kan zijn voor zijn persoonlijk inzicht en vorming.De te voeren actie dient nog slechts te worden toegespitst op het overtuigen van de verantwoordelijken. Het instrument is immers gebruiksklaar en degelijk, er is alleen nog het wachten op de wil van de gebruiker dit instrument ter hand te nemen. (shrink)

In the Netherlands, the legalization of assisted suicide for persons with a death wish without severe illness, often referred to as persons with “completed life” or “tiredness of life,” is intensel...

Sleep has a profound effect on our mood, but insight in the mechanisms underlying this association is still lacking. We tested whether emotion regulation is a mediator in the relationship between fragmented sleep and mood disturbance. The effect of fragmented sleep on the emotion regulation strategies, including cognitive reappraisal, distraction, acceptance and suppression ability, was assessed. We further tested whether the use of these strategies, as well as rumination and self-criticism, mediated the association between fragmented sleep and negative and positive (...) affect. Participants (N = 69) wore an actiwatch and filled in a sleep diary for 12 consecutive nights. They had one control night and one sleep fragmentation night. Emotion regulation ability was assessed with an experimental task. Usage of emotion regulation strategies and negative and positive affect were assessed four times during the day with a survey after the control and sleep fragmentation night. Cognitive reappraisal, distraction, acceptance and suppression ability did not differ between the sleep fragmentation and control condition. However, participants reported higher usage of rumination and distraction after the sleep fragmentation night and rumination significantly mediated the negative association between fragmented sleep and negative affect. (shrink)

BackgroundResearch ethics committees (RECs) are tasked to assess the risks and the benefits of a trial. Currently, two procedure-level approaches are predominant, the Net Risk Test and the Component Analysis.DiscussionBy looking at decision studies, we see that both procedure-level approaches conflate the various risk-benefit tasks, i.e., risk-benefit assessment, risk-benefit evaluation, risk treatment, and decision making. This conflation makes the RECs’ risk-benefit task confusing, if not impossible. We further realize that RECs are not meant to do all the risk-benefit tasks; instead, (...) RECs are meant to evaluate risks and benefits, appraise risk treatment suggestions, and make the final decision.ConclusionAs such, research ethics would benefit from looking beyond the procedure-level approaches and allowing disciplines like decision studies to be involved in the discourse on RECs’ risk-benefit task. (shrink)

The text of the tract De arcubus similibus was published for the first time by M. Curtze in 1887. However, after examining some more Latin manuscripts and the Arabic MS Oxford, Bodleian Library, Marsh 663 it appeared, that Curtze's edition was rather an adaptation. Also Curtze's suggestion that Jordanus Nemorarius was the author was very probably wrong. The author of the tract was the Egyptian mathematician Ahmed ibn Jusuf as appears from the Latin manuscripts, and its translator, very probably, Gerard (...) of Cremona. In the tract Ahmed tried to prove, that the assertion ‘similar arcs are also equal arcs’ was wrong . His starting points were the propositions Euclid III, 20 and 21. Consequently, the tract can be looked upon as a commentary on the third book of the Elements. (shrink)