Summary of the Current Researches Related to Zoology and Botany

1917 Journal of the Royal Microscopical Society  
do not hold themselves responsible for the views of the authors of the papers noted, nor for any claim to novelty or otherwise made by them. The object of this part of the Journal is to present a summary of the papers as actually pubi i s k d , and to describe and illustrate Instruments, Apparatus, etc., which are either new or have not been previously described in this country. t This section includes not only papers relating to Embryology properly sn called, but also those dealing with
more » ... on, Development, Reproduction, and allied subjects. SUMMARY OF CUBREKT RESEARCHES RELATIXG TO divide. The result nould 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 chromoeomes 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 experimented 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 te new, heritable, somatic variations. The fowls were subjected to ethylalcohol, 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 Rocks. 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 o r 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 physiolo ical economy, but except for that point, and the reduced The. mortality among the treated birds was much smaller than among their untreated control sisters. But the numbers involved were small. Immediately after treatment 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 ex eriments the treated birds were on the average 9 . 9 p.c. heavier than t i l l eir untreated sisters. Neither the total amount nor t h e distribution of egg-production were significantly different in the t w o sets of birds. Both treated birds and control birds laid normally and well. Origin of Germ-cells in Chick.t-Franklin P. Reagan supports the conclusion of Swift that the germ-cells originate in a crescentshaped area of the extra-embryonic blastoderm of the chick, anterior to the body-axis a t the line of demarcation between the areas pellncida 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 to develo , or to eome other region where they soon degenerate. I n any w e , t K e 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 yolksac). The artificial production of embryonic hermaphroditism is also rruggested. Ovarian Cycle in Mice.$-H. P. Smith, who with Dr. J. A. Long made a study, extending over ninety-one days, of the-ovulation cycle in activity whic % goes with it, they are very much like normal fowls."
doi:10.1111/j.1365-2818.1917.tb00691.x fatcat:dfqkadbvvbh7nijav2zowqgnvy