308 J. E. WODSEDALEK. 



other observers as "a remarkably clear demonstration of an 

 accessory chromosome" without at first arousing the least 

 suspicion of the hoax. 



"The body in question is nevertheless neither an accessory 

 nor any other kind of chromosome; though this did not become 

 wholly certain until after a study of the entire spermatogenesis. 

 It is in fact of protoplasmic origin, first appearing early in the 

 growth-period outside the nucleus, whence it may be followed 

 uninterruptedly through all the succeeding stages until it is 

 finally cast out of the spermatozoon. Upon dissolution of the 

 nuclear membrane it is left lying near the chromosomes, passes 

 without division into one of the daughter-cells in each of the 

 spermatocyte-di visions, and thus enters but one fourth of the 

 spermatids." 



In the horse the chromatoid body is of a spherical shape and 

 also of a dense and homogeneous consistency, and stains exactly 

 like the chromosomes of the division stages or the chromosome- 

 nucleoli of the growth-period. It is invariably surrounded by 

 a clear area. It makes its appearance in the stages immediately 

 following synizesis and apparently attains its full size rather 

 abruptly, for as a rule even in the earlier growing stages, if it is 

 present at all, it possesses its full size, although in some cases it 

 was found to be somewhat smaller (Fig. 13). Occasionally, in 

 the earliest stages immediately following synizesis one or two 

 very small bodies within clear vacuoles could be detected (Fig. 

 12). Two such small bodies are extremely rare and even the 

 single minute bodies showing the very beginning of the chroma- 

 toid body are not numerous; however, it is quite certain that 

 the body practically always originates as a single element. When 

 the cells attain their maximum size the chromatoid body is 

 invariably present and possesses its full size which makes it very 

 conspicuous (Fig. 14). 



The chromatoid body may be seen anywhere within the cyto- 

 plasm, either near the nucleus or far from it. Sometimes it 

 appears to be in fairly close contact with the cell-wall (Fig. 14). 

 When the nuclear wall disappears and the chromosomes come into 

 full view, it may again be found anywhere in the cytoplasm. 

 Later when the chromosomes arrange themselves for division 



