;90 



Pub. Paget Sound Biol. Sta. 



Vol. 2, No. 55 



Table 4. Action of potassium cyanide on the oxygen consumption 

 of nudihranchs 



Table 5. Action of potassium cyanide on the oxygen consumption of 

 the shore crab 



9. Results and discussion. As shown in the tables the oxygen eon- 

 sumption is in all cases markedly reduced in the presence of potassium 

 evanide. This result is in agreement with that previously found for a 

 number of other organisms. The question arises whether this depression 

 of the oxygen consumption may not be due, in part at least, to some effect 

 of the cyanide on the degree of muscular activity of the animal or the 

 degree of extension of respiratory structures. Particular note was made 

 of these matters during the experiments. In the case of the shore crabs 

 only could any difference in the amount of movement be detected in the 

 presence of evanide as contrasted with movement in normal sea-water. 

 These animals, to my surprise, were very susceptible to cyanide and 

 showed signs of anaesthesia in the 1-5000 molecular solution. Owing to 

 this circumstance they were left in this solution only one hour. In order 

 to eliminate the possibility that the depression of oxygen consumption 

 observed in the case of these animals was due to the anaesthesia three 

 experiments were run using a much more dilute solution, 1-20000 solution. 



