SUMMARY OF CURRENT RESEARCEES 



RELATING TO 



ZOOLOGY AND BOTANY 



(PRINCIPALLY INVERTEBRATA AND CRYPTOGAMIA), 



MICROSCOPY, Etc.* 



ZOOLOGY. 



VERTEBRATA. 

 a. Embryology, t 



Alleged Influence of Lecithin on Determination of Sex.J — R. C. 

 Punnett refers to Russo's experiments, as the result of which he 

 claimed to have brought about a great increase in the relative number 

 of female young produced by rabbits. Punnett prepared an emulsion by 

 shaking up 5 grains of lecithin (Merck) with 100 c.cm. of physiological 

 salt solution (0 ■ 65 p.c). The daily dose for a rabbit was 20 c.cm. of 

 this emulsion made up into a paste with meal, and the treatment was 

 continued for three months before the doe was put to the buck, and 

 for a few days thereafter. Ten does were treated in this way, and 

 they eventually produced 47 young — 24 male and 23 female. From 

 these and other does not treated with lecithin Punnett had 18 litters 

 with 103 young — 54 male and 49 female. The numbers are not large 

 in these experiments, but so far as they go they are entirely opposed to 

 the view that feeding on lecithin has any influence on the relative 

 proportion of the sexes among rabbits. 



Parthenogenetic Segmentation in Birds. § — A. Lecaillon has 

 observed in unfertilised eggs of the fowl a true parthenogenetic 

 cleavage. The segmentation-cells multiply by mitosis, but the ap- 

 pearance is quite different from the normal. It affects only a part of 

 the cicatricula, it proceeds more slowly than in fertilised eggs, and the 

 cells degenerate one after another. 



* The Society are not intended to be denoted by the editorial " we," and they 

 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 pub- 

 lished, 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 so 

 called, but also those dealing with Evolution, Development, Reproduction, and 

 allied subjects. 



% Proc. Cambridge Phil. Soc, xv. (1909) pp. 92-3. 



§ Comptes Rendus, cxlviii. (1909) pp. 52-3. 



