348 



Prof. Farmer, Messrs. Moore and Walker. [Nov. 17, 



cancerous and normal reproductive tissue to be derived from a study of the 

 so-called Plimmer's bodies of cancer.* 



It was shown by one of us in 1895f that, during the prophase of the first 

 maiotic (heterotype) division of the spermatogenetic cells of mammals, the 

 archoplasm undergoes a peculiar and definite series of metamorphoses. In 

 ordinary somatic or premaiotic cells, this body is seen to lie beside the nucleus 

 as a dusky mass of protoplasm, in the centre of which are found the centro- 

 somes. Thus, in these cells, the attraction sphere consists of the archoplasm 

 plus the centrosomes (fig. 3, b, fig. 4, a). 



When, however, we turn from the premaiotic or the somatic cells to 

 the prophase of the heterotype (first maiotic) mitosis, we find these' two 

 constituents have become separated (fig. 4, b). The centrosomes migrate from 

 the centre of the archoplasm, and are eventually seen to he outside that body, 

 and' completely detached from it (fig. 4, c). At the same time the archoplasm 

 itself undergoes a change, small vesicles are developed in its substance (fig. 14), 

 and, at the close of this particular cell-generation, both vesicles and archo- 

 plasm become merged and lost in the general cytoplasm of the daughter cells. 



In the prophase of the second maiotic (homotype) mitosis the same peculiar 

 phenomena recur, and the archoplasm and the vesicles, in like manner, 

 become lost during the later stages of this (homotype) division. In the 

 spermatids, which result from it, the persistent centrosomes can be readily 

 seen to be perfectly disconnected with the new archoplasm which is 

 differentiated in these cells. The archoplasm becomes filled with minute 

 vesicles, as in the two preceding cases, subsequently the vesicles enlarge, 

 and they either fuse together, as in some mammals, or one usually takes the 

 lead and grows larger than the rest, as commonly happens hi the guinea-pig 

 and in man (fig. 15). The body thus formed was originally termed the 

 archoplasmic vesicle in 1895,+ and it is a very conspicuous and constant 

 feature peculiar to the sperm cells of the vertebrata, whilst it has also been 

 encountered by various observers in animals outside that group. 



When fully developed, the archoplasmic vesicle often assumes a size 

 approximating to that of the nucleus itself, the latter being often deformed 

 into a crescentic shape, owing to the enlargement of the vesicle that lies 

 adjacent to it in the cell. In normal spermatids, the vesicle and its contents 

 ultimately form the so-called "cephalic cap" of the spermatozoon (fig. 16, a). 



* See 'Roy. Soc. Proc.,' vol. 76 B, "On tlie Resemblances existing between the 

 'Plirumer's Bodies' of Malignant Growths and certain Normal Constituents of Repro- 

 ductive Cells of Animals," by J. Bretland Farmer, J. E. S. Moore, and C. E. Walker. 



t Moore, ' Internat. Monatschr. f. Anat. u. Physiol.,' 1894. 



| Moore, loc. cit. 



