282 SUMMARY OF CUEKENT KESEARCHES RELATING TO 



divide. The result would be that one-half of the spermatids receive- 



leven' ordinary chromosomes plus X, and the other half eleven plus Y^ 



The number and behaviour of the chromosomes in the spermatogenesis- 



of the white and negro races of man is the same in the material studied. 



Effect of Alcohol on Germ-cells.* — Raymond Pearl has experi- 

 mented with domestic fowls in order to determine whether the continued 

 administration of ethyl-alcohol (or similar narcotic poisons) effects- 

 precise and specific changes in the germinal material, such as to lead to- 

 new, heritable, somatic variations. The fowls were subjected to ethyl- 

 alcohol, methyl-alcohol, or ether in inhalation tanks. The treatment 

 extended over an hour each day, for 130-354 days, with a mean of 

 about seven months. The males used were pure-bred Black Hamburgs,. 

 the females pure-bred Plymouth Eocks. Full brothers and sisters of 

 the " treated " birds were used as controls. 



The results show that "the treated animals themselves are not 

 conspicuously worse or better than their untreated control sisters or 

 brothers. The survivors, i.e. those not killed by accident, after roughly 

 a year and a half of daily treatment, are becoming a bit too fat for their 

 best physiological \conomy, but except for that point, and the reduced 

 activity which goes "with it, they are very much like normal fowls." 



The mortality among the treated birds was much smaller thao 

 among their untreated control sisters. But the numbers involved were 

 small. Immediately after treatrnent began there was an increase in 

 body weight, probably not due to the treatment ; then there was a 

 sharp and prolonged fall ; then there was a steady rise. At the end of 

 the experiments the treated birds were on the average 9 ' 9 p.c. heavier 

 than their untreated sisters. Neither the total amount nor the 

 distribution of egg-production were significantly different in the two- 

 sets of birds. Both treated birds and control birds laid normally 

 and well. 



Origin of Germ-cells in Chick.f — Franklin P. Reagan supports 

 the conclusion of Swift that the germ-cells originate in a crescent- 

 shaped area of the extra-embryonic blastoderm of the chick, anterior to- 

 the body-axis at the line of demarcation between the areas pellucida 

 and opaca ; and that these primitive germ-cells reach the gonad partly 

 by their own wandering, but principally by way of the blood-stream 

 which transports them either to the gonad where they continue ta 

 develop, or to some other region where they soon degenerate. In any 

 case, the extra-regional origin of the germ-cells of the chick is highly 

 probable, and some experiments have been begun by Reagan on very 

 early embryonic castration (by removal of the germ-tract on the yolk- 

 sac). The artificial production of embryonic hermaphroditism is also 

 suggested. 



Ovarian Cycle in Mice.J — H. P. Smith, who with Dr. J. A. Long 

 made a study, extending over ninety-one days, of the ovulation cycle in 



* Journ. Exper. Zool., xxi. (1917) pp. 125-64 (3 figs.), and pp. 165-86 (4 figs.), 

 ■t Anat. Record, xi. (1916) pp. 251-67 (4 pis.). 

 I X Anat. Record, ii. (1917) pp. 407-10. 



