167] THE GOLDFISH AS A TEST ANIMAL— POWERS 47 



and Loevenhart (1901) pointed out the fact that the activity of oxidase of 

 the potato was retarded by KCN. Shafer (1915) found that hydrocyanic 

 acid affects catalases, reductases, and oxidases in insect tissues. Mathews and 

 Walker (1909) showed that very small amounts of KCN is sufficient to check 

 or prevent the spontaneous oxidation of cysteine to cystin both in neutral 

 and alkaline solutions. Loevenhart and Kastle (1903) have shown that 

 hydrocyanic acid inhibits the catalytic activity of solutions of metallic colloids. 

 Claud Bernard (1857) noted that venous blood of an animal poisoned vAih 

 hydrocyanic acid takes on an arterial hue. Geppert (1889) showed venous 

 blood to have a higher oxygen content than normal in mammals poisoned with 

 hydrocyanic acid. Richards and Wallace (1908) found that protein metabo- 

 lism is increased in a dog by poisoning with KCN due in part to the retarding 

 effect on oxidation by the KCN. Loeb and others have shown that oxygen 

 requirement is decreased and that this decrease is greater the greater amount 

 of KCN used. AU have shown that KCN in very small amounts acts as a 

 stimulus to oxidation both in and out of the animal organism. Moore and 

 Moore (1917) have shown that the maturit}^ of fruit was two weeks earUer and 

 that the total 5deld of fruit was larger on tomato plants fumigated with HCN 

 than normal plants. Woodworth (1915) showed that scale insects eggs when 

 fumigated with hydrocyanic acid in amounts not sufficient to kill them hatched 

 earlier than the normal eggs. Townsend (1901) has found that there is an 

 increase in germination in seed fumigated with hydrocyanic acid. And Zieger 

 (1915) in turn has showoi that the activity of the catalase is in proportion to 

 the general metabolic activities in animals. While Child (1915, p. 66 and 

 citations) and others have shown that very small amounts of KCN increase 

 the rate of metabohsm while larger amounts decrease metabolic processes, 

 Mathews (1916, p. 813) suggests that since cysteine oxidizes itself and has 

 many points in its oxidation which resemble respiration there is more than a 

 superficial connection between the oxidation of cysteine and the respiration 

 of the cell. The most favorable hydrogen ion concentration for oxidation 

 is the same as that of protoplasm and both cysteine and protoplasm are poi- 

 soned by many of the same substances, as nitriles, the cyanides, acids, and heavy 

 metals. Their oxidations are catalyzed or hastened in the same manner by 

 iron, arsenic, and certain other agents. Burge and Burge (1914, 1915) have 

 showTi that digestion of a dead round worm in activated pancreatic juice does 

 not take place so long as its body wall is constantly permeated with nascent 

 oxygen. They conclude that the oxidative processes of living parasites 

 enable them to mthstand the enzymes by oxidizing the enzymes in contact 

 vdih them. Lillie (1902) advances the theory that the tissues are protected 

 from autolysis by oxidizing the enzymes in contact with them. Hofmeister 

 (Mathews 1916, p. 83), Verworn (1909, p. 53), Hopkins (1914), and others 

 have held ihat there is no vital matter in the cell and that the chemical trans- 

 formations do not involve any large biogene molecule but only relatively 

 simple compounds in solution. But Pflliger, Du Bois-Reymond (Mathews, 



