26 CHEMICAL AGENTS AND PROTOPLASM [Cn. I 



the movements become so disorganized that locomotion is im- 

 possible, despite accelerated cilia-motion. Finally, the move- 

 ments suddenly cease, death intervening. (SCHURMAYER, '90, 

 pp. 423-426.) The process of excretion seems to be especially 

 affected. Immediately after the addition of a 0.02% solution, 

 the contractile vesicle increases to from 4 to 10 times its normal 

 diameter, and loses its spheroidal form. In a slightly greater 

 dilution, 0.014%, the contractile vesicle momentarily constricts, 

 but in diastole gains twice its normal diameter, and the time 

 between phases of contraction is greatly increased. Thus, the 

 normal rate of contraction for Euplotes at 15 C. is between 

 30 and 35 seconds ; but in a 0.014% solution of strychnin 

 this is diminished to 1 in 500 seconds. Frequently, several 

 vacuoles are formed, and, eventually, the whole body becomes 

 greatly vacuolated, and death intervenes. (RossBACH, '72, 

 pp. 52, 53.) Many higher organisms are not very sensitive 

 to strychnin. Thus, Ascaridse have a considerable resistance, 

 which SCHRODER ('85, p. 307) ascribes to their not opening 

 their mouths in the solution, the poison being thus obliged 

 to pass through the skin. So, too, snails were found by 

 KRTJKENBERG ('80, p. 100) to be very resistant to strychnin. 



Curare, or urare, is an alkaloid, derived from Strichnos 

 species. The commercial substance is very variable in com- 

 position. NIKOLSKI and DOGIEL ('90) have studied the effects 

 of this drug upon various organisms. Upon adding a few 

 drops of a 0.8% solution of curare to water containing an 

 amoeba, the first effect is a shrinking towards a spherical form 

 and a cessation of all movements. Subsequent washing in 

 water ultimately restores the normal movements. As is well 

 known, it paralyzes also the protoplasm of the nerve endings. 



Quinine, or chinin (C 20 H 24 N 2 O 2 ). The "sulphate," which 

 is first produced in the process of extraction, is commonly 

 employed. This is, moreover, more soluble than the pure 

 alkaloid, 1 part dissolving at 9.5 in 788 parts of water. In- 

 vestigations on the action of this poison upon protoplasm have 

 been made especially by BINZ in a series of papers beginning 

 with '67; by ROSSBACH ('72) on Protozoa; by TEN BOSCH 

 ('80) on leucocytes; by O. and R. HERTWIG ('87) on sexual 

 cells; and by KRUKENBERG ('80) on higher Invertebrata. 



