212 Dr Barry on Fissiparous Generation. 



23. The two liberated young cells are endowed with quali- 

 ties resulting from an intimate mixture of the substance pre- 

 viously contained in their parent cell, with that (from the 

 seminal fluid) which their parent cell receives : a third sub- 

 stance being thus produced. The young cells, containing this 

 third substance, are fertilized or undergo a sort of fecunda- 

 tion in their turn ; become parent cells ; produce another 

 generation, which pass through like changes : and so on 

 (Par. 6).* 



24. Such appears to be the nature of the process I wit- 

 nessed in the original cell, constituting the mammiferous 

 germ, and in the cells immediately descended from it. I have 

 since shewn that other cells present appearances denoting a 

 similar mode of origin ; though a parent cell sometimes pro- 

 duces many cells instead of two. 



25. The reproduction of the cell is thus essentially fissipa- 

 rous, its contents undergoing division after having been as- 



* I lately communicated to the Society the fact that I had found, and shewn to 

 others, Spermatozoa within the ovum ; and this after the essential part had divided 

 into two cells. (Plato V., Fig. 1). (In one instance I counted more than twenty 

 in a single ovum). It would thus seem that the ovum, besides being fecundated 

 by a substance received into the part denominated by me the point of fecundation, 

 continues to be influenced by the seminal fluid. I conceive that the spermatozoa 

 may elaborate this fluid, in a manner comparable to that in which the red blood- 

 discs elaborate the liquor sanguinis, (Par. 34.) Perhaps they directly elaborate 

 the contents of the ovum also. (The spermatozoa which I saw within the 

 ovum, gradually disappeared by liquefaction. I thought I saw some of them 

 tvithin, as well as between, the cells contained in the ovum). I think it possible 

 that on the quantity of the so elaborated substance that finds its way into the 

 germ, as well as on the degree of its elaboration, may depend the amount of re- 

 semblance between the offspring and its father. — [I have received a letter from 

 my friend Professor Schwann, dated Loewen, 23d May 1843, informing me of 

 the following experiment performed by him in the spring of 1842, in order to 

 determine the influence of the spermatozoa in fecundation. Having removed a 

 portion of the seminal fluid from the testis of a frog, and diluted the same with 

 water, he filtered it through paper. Ova were then taken from the ovary of a 

 frog, and treated in two ways. To some of them there was added a portion of 

 the fluid that had passed through the paper ; to others, a portion of that which 

 had not passed through. The fluid that had passed through the paper did not fe- 

 cundate, not a single ovum was developed ; while that which had not passed 

 through effected fecundation very well. " From this," says the Professor, " it 

 follows that fecundation requires a substance which is contained in the semin: 1 

 fluid, but which, not passing through the filter, is not dissolved in the fluid."] 



2 



