HUMAN SPERMATOGENESIS: A STUDY OF INHERITANCE. 9 



the individual testis studied by me? This can certainly not be the case. For 

 the man was a healthy one, the cells exhibiting varieties appeared in all respects 

 normal in structure so far as details of the spindle and the other chromosomes are 

 concerned. Further, and this is an important matter, no degenerating late stages 

 of spermatocytes or spermatids were found, though we should expect them were 

 a large proportion of cells affected by disease. Again, the number of perfectly 

 normal spermatozoa was very high for exceedingly few cases were found of 

 spermatozoa presenting marked abnormalities. Yet these results alone did not 

 satisfy me, I wished to see the cells of another healthy man, and therefore wrote 

 Prof. Guyer for some material from his specimen. On sections of the material 

 generously furnished by him I found only a small number of first maturation 

 mitoses, not more than 8 satisfactory lateral views; of these there were 7 eases of 

 condition A, which he regarded as the regular one, also 1 case of the variation C. 

 On his material second maturation mitoses were more numerous, and in 1 of 

 them the variation e was found; it will be recalled that condition e of the secon- 

 dary spermatocytes evidently results from condition C or D in primary spermato- 

 cytes. Therefore, two of the variations found in my material were observed also 

 in that of Guyer. Further, attention may be called to Guyer's fig. 7, which he 

 states "shows also two precociously diverging daughter chromosomes." It ap- 

 pears to me this might be interpreted as a case of variation C, with the allosome 

 D at the upper pole, and a half of d at that pole and the other half at the lower 

 pole. 



Consequently we are justified in concluding the variations observed, at least 



of the allosomes, to be quite normal phenomena. 



We may now summarize the allosome behavior in the primary spermatocytes 

 with respect to their distribution to the secondary spermatocytes, and from this 

 infer their distribution to the spermatids, using the letters D and d to denote 

 the larger and smaller allosome, respectively. In so doing we should recall that 

 each allosome divides only once in the course of the two maturation mitoses, and 

 undergoes one transport (reductional) without division. 



Condition A. 59 cases. Both D and d at one spindle pole. Both would then 

 go to one secondary spermatocyte and in that one divide equationally. 118 

 spermatids would then each contain J/£D and }/<$, while 118 would receive no 

 part of these. This is the most usual condition and the one discovered by Guyer. 



Condition B. 5 cases. D at one spindle pole, d at the opposite pole. One 

 secondary spermatocyte would receive D entire, and the other d entire. These 

 dividing in the secondary spermatocytes would result in 10 spermatids each with 

 %D, and 10 each with 3^jd. 



Condition C. 10 cases. D at one spindle pole, %.d at that pole and l Ad at 

 the opposite pole. Half the secondary spermatocytes would receive only J^d, 

 which does not divide again, consequently from this line would result 10 sperma- 

 tids with y 2 d, and 10 with no allosome. The remaining secondary spermatocytes 

 would receive D and %d; the former would divide in them but not the latter, 

 and there would result 10 spermatids with %D and 10 with %D and l Ad. 



