172 JOHN N. LOWE 



Pouchet ('76) observed that the pigment cells of Gobius niger 

 contracted in strychnine solutions. Romanes ('77) noted that in 

 the medusa Sarsia (sp.) the swimming motions were much 

 accelerated by strychnine, also that convulsions occurred in this 

 and three other forms — Cyanaea capillata, Tiaropsis indicans, 

 and Tiaropsis diademta. Hedborn ('99) has shown that 

 strong doses of strychnine augment the beat of the isolated mam- 

 malian heart (cat), Dogiel ('77) demonstrated a slight increase 

 in the rate of the heart beat of Corethra larvae. Pickering ('93) 

 observed that weak solutions of strychnine had a primary stimu- 

 lating action on the heart muscle of an embryonic chick. Carlson 

 ('06) has found that strychnine in very weak concentrations had 

 a distinct stimulatory action on the heart ganglion of the Limu- 

 lus heart. Stronger solutions produced augmentation followed 

 by paralysis. He was unable to note any primary stimulation 

 on heart muscle. Laurens ('15) observed that if a drop or two 

 of a 1 per cent solution of strychnine was injected into the 

 body cavity of Amblystoma larvae the pigment cells contracted. 



All the above experiments on other tissues show that strych- 

 nine has a primary stimulating action and especially on the 

 motor ganglia. From the evidence of Ballowitz ('93) who dem- 

 onstrated that the pigment cells of fish have a connection with 

 the nervous system, and from the fact that strychnine stimu- 

 lates the nervous system, we are warranted in concluding that 

 strychnine acts directly on the nervous mechanism controlling 

 the melanophores of trout embryos, rather than on the melano- 

 phores themselves. The seat of strychnine poisoning is in the 

 spinal cord, therefore, the melanophores of trout embryos are 

 in all probability controlled in part by the spinal nervous 

 system. 



2. Picrotoxin. Picrotoxin is used as a fish poison. It pro- 

 duces a medullary stimulation and ultimately results in death. 

 When trout embryos are exposed to a 0.25 per cent solution of 

 picrotoxin the pigment cells contract rapidly. The contraction 

 is complete in two to five minutes. The contraction remains 

 for forty-eight to sixty-four hours, if the fish are kept in this 

 solution. The fish live in 0.25 per cent solution for one hundred 



