190 Journal of Comparative Neukologv. 



frogs were kept up to their necks in standing water for twenty- 

 four hours before examination. This was to insure the pres- 

 ence of the maximum amount of moisture in the body. The 

 observations on this series were made August 5-7th. The 

 room temperature at 10 a. m. was 28-29° C, and the temper- 

 ature in the jar containing the absorbing frog ranged from 

 17-21° C. The absorbing frog was left intact for twenty-four 

 hours before examination. 



TABLE II. 



Body weight. Percentage gain. 



Extremes. Average. Average. Extremes. 



Group I 



4 pairs (20.7-31.5) 24-8 18.9^,, (7.5-26.6^^) 



It may be noted in passing that the room temperature 

 being high and the amount of the standing water in which the 

 frogs were placed being only a few litres, the temperature 

 of this water must have become rather high. Moreover, 

 owing to the meteorological conditions prevailing on the edge 

 of Lake Michigan from which the water supply for the labora- 

 tory is drawn, the " hot waves " in summer are accompanied 

 by a fall in the temperature of the lake water delivered to the 

 city, and this expresses itself in the lower temperature of the 

 jar in which the absorbing frog was kept at this time. 



In comparing the percentage increase in Series II with 

 that for Group II of Series I, with which it may be compared, 

 we see that the gain was slightly greater in Series II, a result 

 which was to be expected, because the bodies of the frogs in 

 Series II were more completely saturated with water. This 

 difference between 15. i ^, Series I, and 18.9%, Series II, is 

 sufficient to warrant making arrangements in the tank so that 

 the frogs shall always be in y^. an inch of water, from which 

 they cannot escape. By this means, we are assured that the 

 frog has taken up all the water it can. 



In Series III, we tried the effect of completely eviscer- 

 ating the "absorbing frog " immediately after death, while in 

 other respects the conditions for this series were essentially the 

 same as in Series II. 



