SUMMARY OF CURRENT RESEARCHES 



RELATING! TO 



ZOOLOGY AND BOTANY 



(principally invertebrata and cryptogamia), 



MICEOSCOPY, Etc.* 



ZOOLOGY. 



VERTEBRATA. 



a. Embryology, t 



Origin of Double Monstrosities.^ — Anton Forster gives a critical 

 account of the various interpretations of double monstrosities. The 

 view that asymmetrical double-structure may be preformed even in the 

 unfertilised ovum, is not confirmed by experiment. The view that a 

 bi-nncleate ovum gives rise to duplex development is neither confirmed 

 nor excluded. Polyspermy as a factor is excluded by the experimental 

 results. Artificial disturbances suggest that symmetrical double- 

 developments may be brought about by operating on the fertilised 

 ovum, e.g. by a separation of the first blastomeres, or, much more 

 probably, by a displacement of the cellular material during segmentation, 

 or in the blastula and gastrula stages. The separation and displacement 

 may be due to osmotic pressure or to mechanical causes. Two em- 

 bryonic areas are established, and the result differs with the degree of 

 their subsequent coalescence. There is a long series leading up to twins 

 with one amnion. 



Studies on the Placental — J. Hofbauer discusses the histology, 

 bio-chemistry, and bio-physics (movements and growth-changes of the 

 villi) of the human placenta. The placenta is an assimilating organ for 

 iron, albuminoids, fats, and oxygen ; it produces several ferments with 

 specific functions ; it is no mere filter, but an organ with complex 

 chemical processes, and with internal secretion. The placentar trans- 

 port of bacteria, agglutinins, and anti-toxins is discussed. 



* 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 published, 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. 



t Verb. Pbys. Med. Ges. Wiirzburg, xxxvii. (1905) pp. 235-62. 



§ Grundziige einer Biologie der menschlichen Placenta. Svo (Wien und Leipzig, 

 1 905) ix. and 175 pp., 5 pis. and 2 figs. 



