96 Dr. Barry's renewed Inquiries concerning the 



dating power upon cells lying in the parenchyma of the organs, 

 and becomes assimilated according to the specific constitution of 

 the same. Sometimes^ instead of chyle, as the fecundating sub- 

 stance to be assimilated, there reaches the hyaline of the blood- 

 corpuscles quite another heterogeneous substance, for instance 

 some sort of infectious matter, organic or animal poison, &c., 

 whereby there as surely arise diseased processes of formation, 

 which communicate themselves to the remaining portion of the 

 blood or to the parenchyma of the organs. 



The author refers to a full confirmation of his observations on 

 the remarkable process of cell-formation in the germinal vesicle 

 of the mammiferous ovum, by those of Mr. H. D. S. Goodsir 

 on a cystic entozoon. And as this lies at the other end of the 

 series of organic existences, the operation of the process in ques- 

 tion there, implies its operation in all intermediate ones. 



He then notices an objection made to his observations, pub- 

 lished in 1839 and 1840, when making known the fact that 

 cleavage takes place in the mammiferous ovum also, — that such 

 cleavage is effected by means of cells ; showing that inadequate 

 research led to that objection, and concluding his remarks with 

 the following words : — " After having examined 230 ova found 

 in the Fallopian tube, with the sacrifice of 150 rabbits for em- 

 bryological research, of which rabbits at least a score were de- 

 voted to anatomical inspection for the purpose of enabling me to 

 determine the time at which the ovum leaves the ovary, — no man 

 will wonder that I deem myself competent to judge whether the 

 divisions of the germ are, or are not effected by means of cells. 

 No man who does not examine mammiferous ova in large num- 

 ber immediately before their exit from the ovary, or othei"wise 

 through observations on animals or plants make himself ac- 

 quainted with the germinal-spot-process of division, is able to 

 comprehend the formative process in the mammiferous ovum in 

 any of its earlier or later stages, or indeed to understand the 

 physiology of cells^-." 



A former drawing, fig. 13, shows the mode in which a spiral 

 arises out of cells. The following may serve to illustrate the 

 way in which the twin or double spiral is produced. Every mi- 

 croscopic observer must be familiar with segmented cytoblasts, 



* [In the mammiferous ovum there is no substance that can be called a 

 food-yelk. The germ-cells therefore are not there obscured by a surround- 

 ing jelk-raass, the cleavage of which they govern, as seems to be the case 

 in ova since figured by other observers.] 



