Embryology, with the physiology of generation ... / Translated from the German, with notes, by William Baly ... From Müller's Elements of physiology and supplement.
- Johannes Peter Müller
- Date:
- 1848
Licence: Public Domain Mark
Credit: Embryology, with the physiology of generation ... / Translated from the German, with notes, by William Baly ... From Müller's Elements of physiology and supplement. Source: Wellcome Collection.
372/376 page 132
![The preponderance of nucleated coloured corpuscles in the blood of the very early mammalian embryo, and their gradual diminution in quantity as the foetus increases in age was noticed by Kolliker. In other observations which the writer made with Mr. Pan-et on the blood of two O embryonic sheep, each about seven lines in length, the truth of this remark was fully confirmed, as also of the fact observed by other physiologists that the blood corpuscles of the foetus are decidedly larger than those of the adult. In the blood of each of the embryonic sheep by far the majority of the corpuscles were coloured, had a diameter at least twice as large as that of the red corpuscles in the uterine vein of the parent, and were biconvex in form, often somewhat distorted, and Saturn-shaped; the addition of water brought into view nuclei in almost all of them.* With regard to the development or fresh formation of corpuscles in the blood after the cessation of embryonic life, Kolliker favours the view advo¬ cated by the translator of Muller’s Physiology,j and adopted by many physiologists, that this is effected by the transformation of the pale cor¬ puscles of the blood, which (developed in the liver during embryonic life, after this period) are identical with the corpuscles found in the lymph and chyle. In this transformation the corpuscles possibly pass through transitional stages somewhat similar to those undergone by the pale cor¬ puscles of the embryonic blood, though, if this be so, the whole process must take place most rapidly, for the occurrence of the stage of coloured nucleated corpuscle is one of extreme rarity, and has never been observed in the blood of the human subject. Mr. Wharton Jones states that he has seen it in the blood of the horse, and of the elephant. Dr. Carpen¬ ter,]; however, and some other physiologists are still of opinion that the red corpuscles do not owe their origin to the pale ones, but that they multiply either by the division of each corpuscle into two, as maintained by Dr. Owen Rees,§ or by its breaking up into six or more segments, each of which becomes a young blood-disc, as described by Dr. Barry.|| * Subsequent examinations of the blood of several embryonic sheep of various sizes with the particulars of which the writer has been kindly furnished by Mr. Paget, would seem to prove a constant resemblance, except in form, between the characters of Mammalian blood at all periods of embryonic life before the disappearance of the branchial fissures, and those of the blood of fish, in which animals the branchial apparatus is persistent. And it would appear that those peculiarities which characterize the blood of Mammalian animals during extra- uterine life are assumed by the foetus at the time of, or just after, the closure of the branchial fissures. J Vol. i. page 155. % Principles of Human Physiology, third edition, p. 107. § Gulstonian Lectures, Medical Gazette, March, 1845. || Phil. Trans. 1840. FINIS. London : Printed by S. & J. Bentley, Wilson, and Fley, Bangor House, Shoe Lane.](https://iiif.wellcomecollection.org/image/b29339601_0372.jp2/full/800%2C/0/default.jpg)
