CHROMOSOMES AND MITOCHONDRIA 273 
TaBLE SHOWING THE NUMBER OF CHROMOSOMES IN MAN 
ACCORDING TO Various INVESTIGATORS 
Peeps aed Haptoiw NuMBER INVESTIGATOR Date 
Bardeleben 1892 
Q4 Flemming 1897 
18 (15 or 19)! | Wilcox 1900 
12 Duesberg 1906 
32 Farmer, Moore, and Walker | 1906 
16 Moore and Arnold 1906 
12 or 10 Guyer 1910 
12 or 10 Montgomery 1912 
24( ?) Gutherz 1912 
47 23 or 24 Winiwarter 1912 
34 (33, 38) Wieman 1913 
which became ten bivalent and two accessories in 
the primary spermatocytes. The latter pass un- 
divided to one pole (Fig. 75, 4), and hence two classes 
of spermatozoa result, one with ten ordinary chromo- 
somes, and the other with ten ordinary and two 
accessory chromosomes. Winiwarter (1912), on the 
other hand (Fig. 75, D-E), reports forty-seven 
chromosomes in the spermatogonia and two classes 
of spermatozoa, one with twenty-three and the 
other with twenty-four. The number in the female, 
according to Winiwarter, is probably forty-eight, 
and hence all mature eggs are alike so far as chromo- 
some number is concerned, each being provided 
with twenty-four. If these data are confirmed, it is 
evident that sex in man is determined at the time 
of fertilization and cannot be influenced by changing 
the environment. 
1 Wilcox doesn’t state whether this is the reduced or diploid number. 
T 
