SUMMARY 01' CURRENT RESEARCHES 



RELATIXG TO 



ZOOLOGY AND BOTANY 



(principally invertebrata and cryptogamia), 



MIC BOS COPY Etc.* 



ZOOLOGY. 



VERTEBRATA. 

 a. Embryology, f 



Discovery of Merogony4 — Prof. Yves Delagc replies to Boveri's- 

 claim to be the sole discoverer of merogony, by a historical account of 

 the earlier investigations of the brothers Hertwig (1887) and of his own 

 work. He sums up by saying that the first stimulus came from the 

 experiments of the brothers Hertwig, that Bovcri followed with a proof 

 of the fertilisation of scheinbar hernluse Fragmente, and that Delago 

 himself first definitely proved that the fragments fertilised by him were 

 non-nucleated. The paper also includes a discussion of the question 

 of the permanence of the chromosomes. Delage considers that it i.= 

 proved that a self-regulation of the number of the chromosomes takes 

 jdace, and this disproves Boveri's theory of their individual permanence. 



Cytoplasmic Maturation and Experimentally Induced Partheno- 

 genesis^ — Prof. Yves Delage emphasises the distinction between the 

 cytoplasmic and the nuclear maturation of eggs ; and shows that the 

 number of chromosomes is a specific character of the cell re-established 

 (after merogony for instance) by auto-regulation. In short, the indi- 

 viduality of the chromosomes is a myth. 



Experiments on the ova of sea-urchins, &c, lead him to conclude : — 

 (1) that the hypertonicity of the solutions is a favourable, but not 

 essential, condition ; (2) that different salts have a specific action inde- 

 pendent of their molecular concentration; (3) that salts of manganese 

 are even more energetic than those of alkalis ; and (4) that temperature 

 alone, especially at a " critical moment," may induce parthenogenesis 

 in Aslcrios. Temperature, hypertonicity, the nature of the salt, very 

 slight acidification with 1IC1, may combine in their influence. 



The moment when the nuclear sap diffuses into the cytoplasm is the- 



* 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 papcis as actually published^ and to 

 describe and illustrate Instruments, Apparatus, &c, 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. 



J Arch. Zool. Exper., ix. (1901) pp. 33-9. Cf. this Journal, ante, p. 2oo. 



§ Comptes Rendus, exxxiii. (1901) pp. 316-9. 



