438 l^Iessrs. Koren and Danielssen on the 



We shall indicate the most remarkable features of this me- 

 moir in the author's own woi'ds : " The general result of my 

 observations is, that the process has been altogether miscon- 

 ceived by my predecessors; that no such departure from the 

 ordinai-y plan of development takes place as the fusion of a 

 number of originally distinct ova into a single embryo ; but that 

 each embryo originates in a single ovum ; that it attains to a 

 certain grade of development by the metamorphosis of the con- 

 tents of its own vitellus ; but that its increase in size, and the 

 continuance of its development, depend upon its appropriation, 

 by a process of deglutition or swallowing, of a mass of additional 

 or supplementary vitellus, the want or insufficiency of which 

 occasions its partial or complete abortion. As to the immediate 

 cause of the production of ' monstrous' embryos, therefore — a 

 phfcnomenon which I have found to be far more common than 

 MM. Koren and Danielssen supposed, — I am in accordance with 

 my predecessors, as I attribute it, with them, to the deficiency 

 of nutritive material. But I differ from them essentially, not 

 merely in regard to the mode in which this nutritive material is 

 appropriated, but also in asserting that the production of em- 

 bryos from single ova, instead of being an abnormal and occa- 

 sional phsenomeuon, is one stage in the normal process of deve- 

 lopment." The number and volume of the " egg-like bodies," 

 which is the name given by the author to the eggs enclosed in 

 the capsules, agree with our observations upon these eggs. But 

 he was unable to discover the chorion, which, however, appeared 

 to us to be very distinct, and which could sometimes be seen 

 even after the commencement of segmentation. He did not 

 observe either a germinal vesicle or a germinal spot in these 

 " egg-like bodies," but on causing nearly developed eggs to 

 escape from the ovaries, he found that they were of the same 

 volume as the " egg-like bodies," and furnished with a germinal 

 vesicle and germinal spot. We agree perfectly with this. 



However, Dr. Carpenter states that, independently of the 

 "egg-like bodies," he has found true eggs in each capsule. 

 But, on asking himself what difference there was between these 

 true eggs and the " egg-like bodies," he has only been able to 

 find a very slight variation in their segmentation. He says that 

 the first segments of the vitellus of these true eggs divide into 

 several small parts, and that by this means a clearer peripheric 

 layer is formed, which becomes enveloped in a ciliary membrane, 

 whilst the " egg-like bodies," which are the largest, have not yet 

 undergone segmentation. He also adds, that segmentation cer- 

 tainly takes place in the "egg-like bodies," but that it is not so 

 complete, and appears to be more fractional, and intended to 

 divide each "body" into smaller spheres. Dr. Carpenter also 



