24 CHEMICAL AGENTS AND PROTOPLASM [Ch. I 



causes Medusae to become quiet in 30 minutes, and is fatal to 

 the earthworm 'in a few hours ; Echinoderms are paralyzed by 

 a 0.05% solution in 30 minutes ; Palaemon (after temporary 

 stimulation) is paralyzed by a 0.01% solution in 30 minutes ; 

 Sepiola is killed by 0.005% in less than a minute. (Gkebn- 

 WOOD, '90.) 



Veratrin, Atropin, and Cocaine act upon Vertebrates so as 

 to excite the central nervous system at first, and then to 

 paralyze it. All act, however, as poisons upon undifferenti- 

 ated protoplasm (Protozoa). Thus, Rossbach ('72) found 

 that when Ciliata were subjected to veratrin chloride, and 

 to atropin sulphate, a peculiar rotary movement took place 

 about one end as a fixed axis. Then imbibition of water 

 with great vacuolation of the protoplasm occurred. Later, 

 the contractile vacuole fails to contract, and protoplasmic 

 movements cease a few seconds after. (Cf. Kuhnb, '64, 

 pp. 47, 65, 100.) 



Cocaine is apparently a benzol derivative, closely related, 

 chemically, to atropin. Its formula is thus given: — 



I^CO . CeH,. 



CHa "-C-COO.CH3 



Its action upon Protista has been studied by Charpentiee 

 ('85), Addtjco ('90), Schuemayee ('90, pp. 438-448), Al- 

 BEETONi ('91, p. 318), Danilewski ('92), and Massaet 

 ('93, p. 66); upon sexual cells, by O. and R. Heetwig ('87, 

 p. 159) and Albeetoni ('91, p. 309); and upon tissue cells 

 by Albeetoni. The result has been to show that cocaine 

 first stimulates for a very short time to excessive activity, and 

 then stupefies and paralyzes. With the paralysis, a strong 

 vacuolation of the protoplasm occurs, since the excretory func- 

 tion of the contractile vacuole is inhibited (Schuemayee, '90, 

 p. 439). Cocaine acts similarly upon the nerve centres and 

 muscles of the more differentiated animals. 



