1910.] 



produced hy Ariimal and Vegetable Life. 



641 



conditions are then not those of normal life or growth, since the reaction 

 of the fresh frog was alkaline. 



Starting from Hardy's conclusion {loc. cit.) that acid particles are electrically 

 negative and basic particles positive, Lillie* investigated the movement of 

 certain animal cells. He found that the red corpuscles and smaller 

 leucocytes — in frog's blood — move to the positive, the voluminous leucocytes 

 to the negative. With spermatozoa there is active migration of the sperm 

 head to the positive, the tail having been absorbed in the cane sugar 

 solution used. With teased-out tissue the effect was not so certain, which 

 he suggests may be the result of post-mortem alteration of muscle substance, 

 and of the injury in teasing out the cells. His conclusions are " that the 

 direction and speed of electrical migration of living cells and portions of 

 tissue are chiefly dependent upon the electrical characteristics of their 

 eonstitutent colloids, that animal cell nuclei exhibit a strong tendency to 

 migrate to the positive pole, and that this is strongest in those nuclei in which 

 the proportion of nucleic acid is highest." 



Perrin {loc. cit.), discussing colloidal solutions, observes that "a charge 

 which is raised by the presence in the solvent of a monovalent acid is 

 lowered by a monovalent base," an extension of Hardy's conclusion. 

 Jennings'f paper on " The Eeactions of Electricity in Unicellular Organisms " 

 is a criticism of others by Birnkoff and Greely on the migrations of infusoria, 

 chiefly Parnmceciuni. Greely states that, in his opinion, " the electrical 

 condition of the protoplasm itself determines the motion." 



4. Vegetable Cells. — In the present experiments the flrst clear movement 

 of vegetable matter observed, other than that of diatoms, was of filaments of 

 Vauchcria, which moved to the negative. Volvox aureus moved and burst to 

 the negative, as was also observed by Carlgren.;J: Splmrella plantaginis, a 

 pleurococcus (chlorophyll green alga), a unicelhilar alga, and protococci from 

 moist growths, all moved to the negative. Working by the method described, 

 the following bacteria, when taken from young active growths and examined 

 immediately, moved without exception to the negative : — B. typhosus, 

 B. tuberculosis, B. diphth. avium, B. prodigiosus, B. Lactic acid, B. pijocyaneus, 

 B. coli comm., B. Friedldnder, Sarcina aurantiaca, Sarcirut lutecc, Staph, aureus. 

 Spore-bearing bacillus, Hog cholera, Pneumococcus. Bacteria from cultures 

 which had been standing in the laboratory for some time and were not sub- 

 cultured before being examined, and bacteria which, though sub-cultured 

 2-i hours before use, showed very poor growth, almost invariably moved to 



•* R. S. Lillie, ' Am. Journ. of Physiol.,' 1903, vol. 8, p. 276. 



t H. S. Jennings, ' Journ. Neurology and Psychol.,' 1905, pp. 528 — 534. 



X Archiv f. Anat. a. Physiol.,' Physiol. Abth., 1900, p. 49. 



