EFFECT OF ETHER AND CHLOROFORM ON FISHES. 



239 



definite sort of behavior for comparison with later experi- 

 ments. 



After 100 minutes in this .267, or after 13 minutes in .403 

 (290.1 nig.) a very distinct third type of reaction appeared. 

 This might very appropriately be named the nosing reaction. 

 It was characterized by incessant restlessness and continual 

 change of direction; the fish nosed back and forth in a peculiar 

 uneasy manner, turning around 180 every 2-8 seconds, holding 

 its head always close against the glass side of the tank, and 

 keeping this up for hours. Experiment B. 3 shows how remark- 

 ably this reaction differed from the others. In concentration 

 4-573 (3> 2 9 2 -5 m g-) this nosing reaction was entirely eliminated, 

 and a still different type of reaction appeared (see exp. B. 10). 



This reaction might well be designated as intermediate, since 

 it seemed to be a compromise between the circuiting of exp. B. i 

 and the nosing reaction of higher concentrations, in that it 

 exhibited the slow turning of the former combined with the 

 narrow range of the latter. The range of the nosing reaction in 

 relation to concentration is shown in Table I. It seems that 

 such an apparently precise reaction ought to be found with fish 

 or other aquatic animals in the case of drugs needing standard- 

 ization. Comparison of Table I. with parts of three experiments 

 shown to the right in chart I. will make clear the significance of 



the results attained. 



TABLE I. 



SHOWING RELATION BETWEEN ETHER CONCENTRATION. AND TIME TILL INCEPTION 

 OF THE NOSING REACTION is OBSERVED. 



*No nosing reaction whatever occurred throughout thic experiment. 



III. RESISTANCE. 



I. Materials and Methods. Killing of fish was carried on in 

 closed bottles in which poison solutions of known concentrations 

 were made up. As a rule 4-liter bottles were used, although 



