Donaldson and Schoemaker, Absorption of Water. 193 



TABLE V. 



Loss in Body Weight. 

 Pair. Frog Used as Control. Frog Used for Absorption. 



a i2.i9'o 12.79^0 



3 10. 2^5 II.7<^0 



4 i5-4^c i4-9fo 

 Average 12.4^^ 12.9^ 



The differences in the percentage loss of body weight seem 

 most probably due to slight differences in the motion of the air 

 over the different dishes, thus altering slightly the rate of 

 evaporation. 



We may now state the conditions for Series V. The 



observations were made October i6th and 17th. Both frogs of 



each four pairs were kept in a dry dish for twenty-four hours 



previous to killing. The absorbing frog was left intact in the 



jar at the temperature of running water — I5-I5.5°C. Room 



temperature 10 a. m., 18-22° C. Records for all the pairs 



taken together. The body weights are given first for the 



normal wet frogs and then for the same after drying. 



TABLE VI. 



Percentage Gain in Absorbing 

 Body Weight in Grams. Frog. 



Extremes. Average. Ave rage. Extremes. 



f Normal 31.2-45.4 38.3 \ 



4 pairs j After drying \ 6.9% (0.6-13^0) 



i 24 hrs. 27.2-40.8 33.4 J 



It is to be noted here that the normal frogs had also been 

 dried, their cords having thus lost weight by drying^: hence 

 the gain recorded has been calculated under the most favorable 

 conditions for showing a large gain ; for if the weight of the 

 standard fresh frog cords had been used, the percentage gain 

 would be much less. If we compare the percentage of gain in 

 the spinal cord as shown by frogs of this normal body weight, 



» In the case of two groups of heavy Bull-Frogs (Vide (l) p. 320, Table 6) 

 the loss in the weight of spinal cord as the result of 25 hours drying amounted 

 to i3</o of the normal weight of the cord. In this connection it must be re- 

 membered that the changes in the amount of water take place very readily in 

 the Bull-Frog. 



