SUMMARY OF CURRENT RESEARCHES 



RELATING TO 



ZOOLOGY AND BOTANY 



(principally invertebrata and cryptogamia), 



MICROSCOPY, Etc.* 



ZOOLOGY. 



VERTEBRATA. 



a. Embryologry.f 



Segmentation induced by Sperm-Extract. J — Herr Hans Winkler 

 has succeeded in inducing cleavage-phenomena in ova of Sphser echinus 

 granularis and Arbacia pustulosa by application of " sperm-extract." The 

 extract was made by shaking spermatozoa in distilled water and filtering 

 half-a-dozen times. The cleavage, which occurred in some ova, was 

 regular to the four-cell stage, and then abnormal. Control experiments 

 were made. Mitoses were observed. The author rejects Loeb's idea 

 that the spermatozoon introduces certain metallic ions into the ovum. 



Alleged Transmission of artificially induced Epilepsy in Guinea- 

 pigs^ — Herr Max Sommer has repeated Brown-Sequard's famous expe- 

 riments, and the net result is absolutely the opposite of that reached by 

 the French physiologist and by Obersteiner. Sommer finds no support 

 in this direction for the supposed transmission of modifications. 



Multinucleate Ova.|| — S. von Schumacher and C. Schwarz describe 

 a remarkable case, the abundant occurrence of multinucleate ova and 

 of follicles with several ova in the ovary of a woman of forty-two, the 

 mother of ten children. 



Envelopes of Hen's Egg.T — Prof. Max Schuller has succeeded in 

 demonstrating the existence of a layer of epithelial cells on the inner 



* 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, &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, 

 t'ut also those dealing with Evolution, Development, Reproduction, and allied sub- 

 jects. 



t Nachr. Ges. Wiss. Gottingen, 1900, Heft 2, 7 pp. See Zool. Centralbl., vii. 

 (1900) pp. 551-2. 



§ Dissertatio, Jena, 1900, 46 pp. See Zool. Centralbl., vii. (1900) pp. 478-80. 



|| Anat. Anzeig., xviii. (1900) pp. 1-3 (6 tigs.). 



f Op. cit., xvi. (1899) pp. 460-7 (7 figs.). 



