SUMMARY OF CURRENT RESEARCHES 



RELATING TO 



ZOOLOGY AND BOTANY 



(principally invertebkata and cryptogamia), 



MICROSCOPY, Etc.* 



ZOOLOGY. 



VEETEBRATA. 

 a. Embryolog-y. t 



Determination of Sex.J — Russo has made some very interesting 

 experiments on the determination of the female sex in rabbits. He 

 dosed rabbits with lecithin, administering it in various ways. He 

 injected it into the peritoneal cavity, or subcntaneonsly, or introduced it 

 through the mouth. The result was an accumulation of deutoplasinic 

 material in the ovarian follicles and in the oocytes. Animals treated in 

 this way, and subsequently mated, had always more female than male 

 offspring. Sometimes all the offspring were female. 



In the normal ovary Russo distinguished two kinds of ova, some 

 which are rich in nutritive material deposited in the zona pellucida and 

 in the vitellus, and others which have little or none. In young rabbits 

 of five or six months the ova have little vitelline material, no chromidial 

 corpuscles, and a clear zona pellucida. This is a sign of deficient nutri- 

 tion, and these very young ova tend to be male-producing. As the 

 nutrition of the ovary improves with age the ova become better equipped 

 with embryoplasmic material, and tend to be female-producing. The 

 ovary is a very plastic organ, and by lecithin-treatment the number of 

 female-producing ova may be increased. It may also be that lecithin- 

 treatment of the males affects the sperms (in their mitochondrial appa- 

 ratus) in a similar way. 



The author gives an account of the germinal epithelium, the granulosa, 

 the zona pellucida, and the chromatic bodies in the ooplasm. Statistics of 

 the experiments and details as to the methods are duly submitted. 



State of Ovary during Pregnancy.§ — 0. 0. Fellner finds that from 

 the histologist's point of view it is impossible to speak of a cessation of 



* The Society are uot 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- 

 lislicd, 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. 



\ Studien iiber die Bestimmung des weiblichen Geschlechtes. Jena (1U09) 

 105 pp. (32 figs.) § Arch. Mikr. Anat., lxxiii. (l'JO'J) pp. 288-305. 



