ZOOLOGY AND BOTANY, MICEOSCOPY, ETC. 129 



during the sixth and seventh years of an experiment on the modification 

 of mammalian germ cells by the treatment of parental generations with 

 alcohol. In general it may be stated that the oflFspring produced when 

 treated males were paired with normal females were inferior in several 

 respects as compared with other offspring from the same normal mothers 

 bred to control males of exactly the same original stock. Further, 

 when the male offspring from treated fathers were mated with normal 

 females, the individuals resulting from such matings were as a group 

 decidedly inferior to the young produced by normal females when mated 

 with control males. This group inferiority was present not only in the 

 grandchildren but in the next generation as well. In general terms, an 

 experimental treatment may act upon the germ cells of an animal so as 

 to modify them. They are changed in some way which lowers their 

 ability to react normally in combination with germ cells from another 

 individual. Thus zygotes are produced which tend to develop abnor- 

 mally, grow slowly, or die during early stages. The subnormal condition 

 may be continued through a number of generations beyond the animals 

 directly treated. J. A. T. 



Amnion-Formation in a Bat.— A. Celestixo da Costa {C.R. Soc. 

 Biol. Paris, 1919, 82, 588-90). In one of the Microcheiroptera, 

 Miiiiopterus schreibersii, there is a hollowing out of the embryonic disc 

 to form a closed, relatively large cavity, comparable to the primitive 

 amniotic sac in Pteropus and other forms. At this stage the developing 

 egg is a vesicle with a trophoblast wall, containing two other vesicles. 

 One is hollowed out in the ectoderm of the embryonic disc. The other, 

 much the larger, is the endodermic or umbilicar vesicle, its wall being the 

 primary endoderm. The ectodermic cavity is quite distinct from the 

 subsequent tropho-ectoblastic cavity. Later on the amniotic folds form 

 the definitive amnion. J. A. T. 



Amnion Formation in Mammals. — A. Celestino da Costa {C.R. 

 Soc. Biol. Paris, 1919, 82, 60-4-5). As van Beneden indicated, there 

 is in some cases a primordial amniotic cavity formed within the em- 

 bryonic disc, preceding the tropho-ectoblastic space, just as that precedes 

 the definitive cavity delimited by the amniotic folds. This is seen in 

 Jliniopteriis, Rhinolophus, Sus, and some other types. But in some 

 other cases — e.g. hedgehog, mole, rabbit, carnivores — the primordial 

 amniotic cavity is rudimentary or absent, and the amnion is formed- 

 from folds. Or, thirdly, the amnion may be formed by excavation of 

 the embryonic disc and histological differentiation of the walls of the 

 primordial cavity, which persists. This is seen in Primates, GaUopithecus, 

 Pteropus, guinea-pig, and some other forms. J. A. T. 



Effect of Cytolysins on Embryos. — M. F. Guyer and E. A. Smith 

 {Journ. Exper. ZooL, 1918, 26, 65-82). Lens tissue of rabbits and 

 mice injected into fowls excites the production of specific anti-bodies. 

 If the serum, sensitized by the presence of these, be injected into 

 pregnant rabbits, the anti-bodies may attack the lenses of the unborn 

 young. The reaction is not invariable, however, since a majority of 

 even all of the individuals of a litter may not be acted upon, or a given 



