A Study of Growth 21 



48.08, the largest percentage obtained for animals taking three 

 pieces of beef per week, despite the fact that two individuals did 

 not eat after the first two weeks, which must have lowered the 

 total increment. These results are also in harmony with the 

 individual records showing that the less the initial weight the greater 

 is the percentage increment. 



(<:) As to the other question which arose as a possible factor 

 in accounting for the variations in the results, viz: the effect of 

 moulting; the data were not sufficient upon which to base a sug- 

 gestion. 



II INFLUENCE OF TEMPERATURE 



The series of experiments of 1906-07, the object of which was 

 to test the effects of temperature above and below the normal on 

 the rate of growth, was repeated. In the former series it was 

 impossible to show the rate of growth at different temperatures 

 because the amount of beef taken by the animals kept at a low 

 temperature, 10° C, was insufficient to preserve equihbrium of 

 those at 20° C. and 30° C. 



In the present series the temperature conditions were practically 

 the same as before, but the feeding was modified somewhat. 



Six sets, consisting of ten individuals each, were kept at three 

 different temperatures, as follows: 



Average 



temperature 



deg. C. 



Set D (Table XXI) lo 



Set Di (Table XXII) 20 



Set D2 (Table XXIII) 3° 



Set £1 (Table XXIV) 20 



Set E2 (Table XXV) 3° 



Set F (Table XXVI) 3° 



The amount of beef taken by D was used as a basis for D^ 

 and D^ For the first three weeks the feeding was very regular, 

 all eating three pieces per week, averaging 105 mg. each; after this 

 time, because of the effect of low temperature, the animals became 

 difficult to feed. 



