238 HAROLD D. CLAYBERG. 



The following studies were carried out with the idea that a 

 reaction might prove more definite, and perhaps less variable 

 than time of death. 



3. Chloroform. Bullheads and suckers were used in a series 

 of experiments which began with low concentrations which were 

 increased in the successive trials. Both species showed con- 

 siderable individual variation and in general failed to react to 

 most concentrations. Both species showed some positive reac- 

 tions in the case of .14 c.c. per liter (213.8 mg.) and a few nega- 

 tive reactions occurred in somewhat higher concentrations. 

 There appeared to be no definite relation between reaction and 

 fish size. The general failure to give definite positive or negative 

 reactions may be due to a paralysis of the sensory endings with 

 which fishes are known to recognize substances in solution in 

 water. 



4. Ether. Bullheads alone were used, but a complete series 

 of ten experiments were run in which concentration ranged from 

 .267-4.573 c.c. per liter (192.24-3292.56 mg.). These solutions 

 were all distinctly non-fatal because no symptoms of even partial 

 loss of equilibrium were observed. Although some experiments 

 ran for three hours, the fish exhibited no true positive or negative 

 reaction when any experiment as a whole was considered. If, 

 however, a small piece of one were carefully chosen an impression 

 of reaction in either direction could be obtained from any experi- 

 ment. The piece chosen from experiment B. 3 on chart I. was 

 chosen for another purpose but it appears to show negative 

 reaction. This is not the case as the whole experiment rather 

 points to indefinite reaction. 



While tank end preference was nil, the general behavior of the 

 fish underwent definite change twice during the gradual increase 

 in strengths of the poison used. Chart I. contains critical experi- 

 ments of \vhich repeated mention will be made through the rest 

 of the reaction discussion. Experiment B. I was the first of the 

 series and shows that circuiting predominated; but occasional 

 little notches occur in the curve that are absent in the sucker's 

 curve (exp. A. 6) and w r hich are very suggestive of the behavior 

 of the bullhead to higher concentrations. Thus experiment B. I, 

 having a concentration of .267 c.c. per liter (192.2 mg.), fixes a 



