EFFECT OF TEMPERATURE ON ANIMAL TISSUES. 47 



been exposed to the low temperature began to produce moths, 

 and all of them had completed the metamorphosis by February 

 3. None of the chrysalids that had been kept at a temperature 

 of 20 C. showed any signs of development. Several of the 

 cocoons were opened, but the chrysalids were in the same con- 

 dition, as far as could be seen, as when they were collected. 



This result indicated that a lowering of the temperature at 

 least accelerates the metamorphosis of the chrysalids. To de- 

 termine whether the effect of the low temperature on the larva 

 consisted in an extraction of water from the protoplasms, as was 

 the case in the low temperature experiments on the Protozoa, 

 the experiment was now varied as follows : The cocoons, that 

 had been kept constantly at a temperature of 20 C., were now, 

 on February 3, divided into three lots. One lot was retained at 

 the room temperature, 2OC., another lot was exposed outdoors 

 to a temperature of about 10 C. for seven days, and the third 

 lot of four cocoons was placed in a desiccator over sulphuric 

 acid for two days. These four cocoons, while in the desiccator, 

 lost water as is shown by the following record of weights : 



Weight when Placed in Weight when Removed from 



Desiccator, Feb. 3. Desiccator, Feb. 5. 



1. I7-0555 g- 17-031 g- 



2. 15.184 g. 15.173 g. 



3. 16.630 g. 16.603 g. 



4- i5-"5 g- 15-095 g- 



These four cocoons produced moths on March 4, 10, 13 and 

 14. On March 24, moths emerged from the cocoons of the 

 second lot that had been exposed to the low temperature, but 

 on March 26 the cocoons of the control series that had been 

 kept continuously at the room temperature produced moths 

 also, showing that this last exposure to a low temperature was 

 too late to have any effect. The desiccation hastened the devel- 

 opment by about two weeks. We see from this experiment that 

 the original exposure to a low temperature in November, soon 

 after the cocoons were first brought into the laboratory, hastened 

 the development by two months, and that the desiccation within 

 two months before all the cocoons produced moths sufficed to 

 accelerate the development materially. These experiments are 

 far from satisfactory because of lack of material, but they furnish 



