SUMMARY OF CURRENT RESEARCHES 
RELATING TO 
ZOOLOGY AND BOTANY 
* 
(principally inyertebrata and cryptogamia), 
MICROSCOPY, Etc.* 
ZOOLOGY. 
VERTEBEATA. 
a. Embryology, Evolution, Heredity, Reproduction, 
and Allied Subjects. 
Irradiation of Young Guinea-pigs. — M. Fraenkel (Strahlen- 
therapie , 1921, 12 , 272 ; and Journ. radiol. et electrol., 1921, 5 , 429). 
Experiments with Rontgen rays on young or developing guinea-pigs. 
An animal was irradiated four times after birth. It remained abnormally 
small, but gave birth in normal time to two young ones. These, not 
irradiated, remained still small, and gave birth to young ones which 
were sterile. The absence of hair on the head and back, provoked in 
the first generation by the irradiations, recurred in the following genera- 
tions. Autopsy of the animals showed a large accumulation of fat. 
Cystic degeneration of the ovaries was observed alike in the irradiated 
and non -irradiated animals. J. A. T. 
Effects of Altered Oxygen Pressure on Dove Embryos.— Oscar 
Riddle ( Proc.Soc . Exper.Biol. and Medicine, 1921, 18 , 102-5). Com- 
pared with hatched young or adults the dove embryo has very inferior 
powers of adjustment to either high or low oxygen pressures. The 
earliest stages, in fact, wholly lack the usual or other apparent mechanisms 
of respiratory compensation. Monsters result from altered oxygen 
pressure on young embryos. Age is the chief factor involved in the 
death or survival. Embryos of 8 to 10 days and older are like hatched 
individuals in being able to survive the highest percentages of oxygen. 
The youngest stages best survive decreased pressures of oxygen. For 
these stages the oxygen may be reduced to 9 to 10 p.c. for 24 hours. 
It is clear, however, that this “ cold-blooded ” stage of the bird embryo 
is unable to reduce the oxygen demands of the tissues to a further 
* 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. 
