692 RECORD OF CURRENT RESEARCHES RELATING TO 



KECOKD 



OF CURRENT RESEARCHES RELATING TO 



INVERTEBEATA, CEYPTOGAMIA, MICROSCOPY, &c. 

 including Embryology and Histology generally. 



ZOOLOGY. 



A. GENERAIi, including Embryology and Histology 

 of the Vertebrata. 



Cell-division in Animals.* — An important researcli on this subject 

 is published by Professor Peremeschko, of Kiew, who has studied 

 the epidermis, connective-tissue corpuscles, white blood-corpuscles, 

 and spindle-shaped cells from which the blood capillaries are de- 

 veloi^ed, in the transparent larva of the newt (Triton cristatus). 



Method. — For the examination of the living cells it was found 

 convenient, although not absolutely necessary, to curarize the larva. 

 One part of curare was dissolved in 100 of water, and 100 of 

 glycerine added : five to ten drops of this fluid were added to a watch- 

 glass of water, in which the larva was placed. When the movements 

 had become slow and feeble, the animal was removed to a slide, a 

 cover slip placed on the tail, the most convenient part for study, and 

 the rest of the body covered with moist blotting-paper. The larva 

 recovers from the effects of the drug after eight to ten hours, and can 

 therefore be used over and over again. 



Immersion in 3 per cent, alcohol or ether was found useful if 

 the observation was not to be continued long. Sodium chloride solu- 

 tion (1 per cent.), iodized serum, solution of sugar, &c., were also 

 found of service, as rendering certain appearances more distinct. 



Absolute alcohol was found to be the best hardening fluid : small 

 pieces of the tail were placed in it for a quarter of an hour, stained 

 with hfematoxylin, fuchsin, or neutral carmine solution, and mounted 

 in glycerine or dammar. Solutions of gold chloride and osmic acid 

 (i *o I- per cent.), and silver nitrate (i per cent.) were also employed. 



Bcsidts. — After treatment with curare or sodium chloride solution, 

 the epithelial cells of the epiderm were observed to become much 

 better defined, and spaces to appear between them, crossed by delicate 

 filaments ; these were evidently pseudopodial processes, arising as a 

 result of the contraction of the cells induced by the action of the 

 reagent. 



Changes in the form, size, and arrangement of the intranuclear 



filaments were directly observed ; the changes, however, were so slow 



that no actual movement could be seen. The changes of the dividing 



nucleus described by other observers were seen, and it was further 



* 'Arch. Mikr. Anat.,' xvi. (1879) p. 437. 



