SUMMARY OF CURRENT. RESEARCHES 



RKLATINQ TO 



ZOOLOGY AND BOTANY 



(PRINCIPALLY INVERTEBRATA AND CRYPTOGAMIA), 



MICEOSCOPY, Etc.* 



ZOOLOGY. 



VERTEBRATA. 



a- Embryology, t 



Alleged Influence of Electric Discharges in Inducing Partheno- 

 genesis. J — Yves Delage has come to the conclusion that electric dis- 

 charges do not in themselves induce parthenogenetic development. Apart 

 from electrolytic effects, an electric current has no influence in this 

 connection. Electrolysis has a feeble influence as a factor in partheno- 

 genesis, through the acids and alkalis formed at the electrodes. Minimal 

 quantities of metallic salts very injurious in slightly larger doses, e.g. 

 sulphate of copper and chloride of zinc, are active agents in partheno- 

 genesis. Their activity is notably increased by a slight acidification. 

 Various substances without aoid or alkaline reaction, in particular formol 

 and alum, are active parthenogenetic agents, and acidification helps. The 

 same is true of almost infinitesimaliy small doses of colloidal hydrate of 

 iron. Delage adheres to his view that the artificial inducing of the 

 formation of a vitelline membrane, and the dissolution of the nuclear 

 membrane, sets the egg developing parthenogenetically. 



Vitelline Membrane in Egg of Birds.§ — A. Lecaillon has studied 

 the egg of the blackbird in this connection. He finds that the so-called 

 vitelline membrane has three layers. The innermost shows no cellular 

 structure ; the middle one is an epithelium in process of degeneration ; 

 the outermost one consists of fibrillar connective-tissue. In the advanced 

 ovarian ovum there is a follicle with these three layers just as in the 

 laid egg. Thus what is called the vitelline membrane consists of part 

 of the follicular theca, and would be better called vitelline capsule. 



In another paper || he gives minute data in regard to the structure 



* 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. 



f This section includes not only papers relating to Embryology properly so 

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

 allied subjects. % Comptes Eendus, cxlix. (1909) pp. 890-6. 



§ Op. cit., cl.(1910) pp. 240-2. 



C.R. Soc. Biol. Paris, lxviii. (1910) pp. 218-19. 



