SUMMARY OF CURRENT RESEARCHES 
RELATING TO 
ZOOLOGY AND BOTANY 
(PRINCIPALLY INVERTEBRATA AND CRYPTOGAMIA), 
MICROSCOPY, Etc.* 
ZOOLOGY. 
VERTEBRATA. 
a. Embryology, Evolution,' Heredity, Reproduction, 
and Allied Subjects. 
Spermatogenesis of Man. — Theophilus S. Painter ( Proc . Amer. 
Soc . Zool. in Anat. Record , 1922, 23 , 129). There are 48 chromosomes 
in dividing spermatogonia in both the white and negro testes. Two of 
these 48 chromosomes have no synaptic mates of the same size or 
shape. These are the X and Y sex-chromosomes. Primary spermato- 
cytes show 24 chromosomes. The X-Y sex-chromosome consists of an 
element the two halves of which are very unequal in size. When 
division occurs, the X chromosome goes to one pole, and the Y to the 
other. J. A. T. 
Experiments with Spermatotoxins. — M. F. Guyer {Journ. Exper. 
Zool., 1922, 35 , 207-23, 1 fig.). Spermatotoxic sera, prepared by 
injecting fowls repeatedly with the spermatozoa of rabbits, are toxic in 
vitro for the spermatozoa of both rabbits and guinea-pigs. When 
introduced into the blood stream of male rabbits at intervals of four or 
five weeks, such serum produced partial or complete sterility. Inactiva- 
tion of many spermatozoa, reduction in numbers, or even complete 
disappearance from the semen, occurred. In one case there were 
disintegrative changes in the seminiferous tubules. The blood-serum 
of a rabbit injected intravenously with its own spermatozoa becomes 
highly toxic for the spermatozoa of rabbits, including its own. The 
spermatozoa of a rabbit which has been repeatedly injected with its 
own semen are much less viable, both in normal rabbit serum and in 
spermatotoxic serum, than are normal spermatozoa. Presumably such 
* The Society does not hold itself responsible for the views of the authors 
of the papers abstracted. The object of this part of the Journal is to present 
a summary of the papers as actually published , and to describe and illustrate 
Instruments, Apparatus, etc., which are either new or have not been previously 
described in this country. 
