SUMMARY OF CURRENT RESEARCHES 



RELATING TO 



ZOOLOGY AND BOTANY 



(principally invertebrata and cryptogamia), 



MICROSCOPY Etc.* 



ZOOLOGY. 



VERTEBRATA. 

 a. Embryolog-y. t 



Artificial Parthenogenesis in Arbacia induced by the Use of 

 Sea-water concentrated by Evaporation.} — S. J. Hunter finds that 

 sea-water condensed until it is isotonic with Loeb's 10 p.c. to 15 p.c. 

 2^ n scdium chloride solution will induce artificial parthenogenesis in 

 the ova of the sea-urchin Arbacia. Sea-water with osmotic pressure- 

 perceptibly less or greater than the 10 to 15 p.c. solution of 2.^ n 

 sodium chloride will not produce artificial parthenogenesis. Further- 

 more, it is evident that a certain osmotic index or degree of pressure- 

 is essential for artificial parthenogenesis. These observations obviously 

 supply an interesting confirmation of Loeb's osmotic theory of artificial 

 parthenogenesis. 



Problem of Fertilisation^ — Th. Boveri has published a terse up- 

 to-date exposition of the processes of fertilisation, with a critical dis- 

 cussion of the meaning of the various steps. Perhaps the most 

 significant part of the lecture is that in which he suggests some modi- 

 fication of the view that one of the chief functions of the spermatozoon 

 is to import a centrosome into the inert ovum. Morgan and others- 

 showed that alterations in the saline composition of the sea- water 

 resulted in the appearance of bodies like centrospheres in the ova of 

 sea-urchins, &c. ; Loeb showed that in similar conditions (already sum- 

 marised) artificial parthenogenesis resulted ; Wilson noticed that in 

 Loeb's experiments bodies like centrospheres appeared in the unfertilised 

 ova and seemed to initiate the segmentation ; Boveri now suggests " that 

 it is not a centrosome as an organised structure which is introduced into 

 the egg, and which there starts the segmentation processes, but rather 



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

 aot hold themselves responsible for the views of the authors of the papers noted, 

 aor 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 published, and to 

 describe and illustrate Instruments, Apparatus, &c, which are either new or hav& 

 cot been previously described in this country. 



+ This section includes not only papers relating to Embryology properly so called, 

 but also those dealing with Evolution, Development, Reproduction, and allied subjects,. 



t Amer. Journ. Physiol., vi. (1901) pp. 177-80. 



§ Das Problem der Befruchtung, Jena, 1902, 8vo, 48 pp. 



