242 W. J. CROZIER. 



With the other species employed in the experiments this effect was 

 not seen. In each form used, however, strychnine in saturated 

 solution (volume 0.5 c.c.) produced temporary but violent con- 

 vulsive movements, incoordinated trembling movements of legs 

 and prolegs, followed by quiescence, and often a rather strong 

 ventral flexure and paralysis of the appendages. Twelve hours 

 was sufficient to permit full recovery from the effects of even such 

 doses of strychnine. Experiments with various aquatic larvae 

 (especially of Pscphenus}, and upon crayfish, further point to the 

 very slight toxic effect of strychnine, and likewise show the de- 

 tectable tendency to produce opisthotonic curvature. Crayfish, 

 even when holes have been punctured in the cuticula, presumably 

 facilitating absorption of the drug, were found to live for 9 days 

 in a strychnine solution originally i : 1000 and slowly evaporated 

 during the nine days that the test continued. The backward swim- 

 ming of the crayfish is impeded by the strychnine, while there is 

 maintained an incessant forward creeping. 



In contrast with this behavior of the strychninized arthropod 

 neuromuscular system, in annelids we observe typical " reversal of 

 inhibition," although in the earthworm 9 it is perhaps more difficult 

 to demonstrate than is true with leeches. Several species of 

 leeches have been studied in dilute strychnine sulphate, and for 

 present purposes the following findings may be cited : there is pro- 

 nounced contraction of the dorsal longitudinal musculature, relax- 

 ation of the ventral, while in response to local irritation the cus- 

 tomary behavior of longitudinal, transversal, and dorsoventral 

 muscles is completely reversed by the drug. 



ATROPINE. 



Injection of i per cent, atropine sulphate, 0.5 c.c., produced in 

 all forms studied an abrupt loss of creeping ability, within i 

 minute of the injection; this was followed by a period of seg- 

 mental tremblings, involving some ventralward contraction (the 

 animals lying on the side), and within 5 minutes after injection 

 there appeared a very striking reversal of the behavior of the 

 prolegs. Normally, and especially, in their natural use, when the 

 creature creeps on the edge of a leaf, slight tactile stimulation of 

 the ventrum between the legs suffices to induce the extension of 



