Paper - The Borderland of Embryology and Pathology: Difference between revisions

Revision as of 12:30, 11 July 2015

While on the one hand pathology is, rightly enough, the handmaid of medicine, on the other hand she is also a science in her own right. We pathologists are thus not only technicians and advisers to the clinician; we are, or should be, also biological scientists, interested in the fundamental properties of living matter in both disease and health. It is good for us periodically to leave the hospital ward and laboratory, and to take a birds-eye survey of progress in related branches of biology which, we may be sure, will have important bearings on our own. One of the most relevant of these is embryology; and my intention in this lecture is to show the significance for pathology of discoveries made by experimental embryologists since the beginning of the present century.(1)

Epigenesis versus Preformation: Of fundamental significance for both embryology and pathology is the concept of epigenesis, namely that the egg is a simple structure which does not contain any kind; of preformed representation of adult structure and that embryonic development consists in a progressive creation of complex structure stage by stage. This principle was clearly enunciated by Aristotle in the fifth century B.C., and again 2,000 years later by William Harvey who in his "De generations animalium" (i651) said of the egg "no part of the future offspring exists de facto, but al parts inhere in potentia." Again, vertebrates "are made by epigenesis, or the superaddition of parts."..."A certain order is observed according to the dignity and use of parts, ...as a ship is made from a kell, and as a potter makes a vesel."

As we shall se, modern experimental embryology has fully confirmed the principle of epigenetic development. Healthy eggs are not predetermined to grow into healthy adults, for various injurious agencies in the environment of the egg and embryo can interfere with its development and lead to malformations or other anomalies. Most of the recent experimental work in this field has been done on amphibian embryos, so that it is necessary to recall briefly the early development of the amphibian egg.

Reference

PMID 15426876

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930017

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930017/pdf/bullnyacadmed00460-0016.pdf

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+While on the one hand pathology is, rightly enough, the handmaid of medicine, on the other hand she is also a science in her own right. We pathologists are thus not only technicians and advisers to the clinician; we are, or should be, also biological scientists, interested in the fundamental properties of living matter in both disease and health. It is good for us periodically to leave the hospital ward and laboratory, and to take a birds-eye survey of progress in related branches of biology which, we may be sure, will have important bearings on our own. One of the most relevant of these is embryology; and my intention in this lecture is to show the significance for pathology of discoveries made by experimental embryologists since the beginning of the present century.(1)
+Epigenesis versus Preformation: Of fundamental significance for both embryology and pathology is the concept of epigenesis, namely that the egg is a simple structure which does not contain any kind; of preformed representation of adult structure and that embryonic development consists in a progressive creation of complex structure stage by stage. This principle was clearly enunciated by Aristotle in the fifth century B.C., and again 2,000 years later by William Harvey who in his "De generations animalium" (i651) said of the egg "no part of the future offspring exists de facto, but al parts inhere in potentia." Again, vertebrates "are made by epigenesis, or the superaddition of parts."..."A certain order is observed according to the dignity and use of parts, ...as a ship is made from a kell, and as a potter makes a vesel."
+As we shall se, modern experimental embryology has fully confirmed the principle of epigenetic development. Healthy eggs are not predetermined to grow into healthy adults, for various injurious agencies in the environment of the egg and embryo can interfere with its development and lead to malformations or other anomalies. Most of the recent experimental work in this field has been done on amphibian embryos, so that it is necessary to recall briefly the early development of the amphibian egg.
+===Reference===
 <pubmed>15426876</pubmed>