
Ce EO ENE ge es We ee ey ee 
CE BET EAG TG eS FT! BAF HOE ES Oy PEP BOTA Por: aa ae” 
Sy ten ge Met 

1914] Longevity of Insects 343 
alive for so long. The effect of ether on plants is similar to 
hibernation and since the action of ether is probably a drying, 
one, this may throw light on the importance of moisture in 
hibernation. Hunter (24) has found that dryness is desirable 
for hibernation—he finds that more weevils die during hiberna- 
tion from exposure to moisture than from cold, on the other 
hand, high temperature and moisture are the best conditions 
for weevil larve to develop. Sanderson quotes Tower as 
keeping potato beetles in hibernation for eighteen months in a 
dry atmosphere. Immediately when placed at a normal 
humidity, they immerge from hibernation. Donaldson (14) 
finds that frogs differ in the rate of reabsorbing water during 
summer and hibernation—it being more rapid in the former— 
he also finds that the water content of the spinal cord varies 
with the season—during the growth period (May 30 to July 1) 
it is high and gradually diminishes towards the end of the season. 
Rulot (45) has found that during hibernation, the production 
of metabolic water sometimes falls to zero in the bat. Hatai 
(21) has found that the effect of partial starvation on the 
nervous system is to decrease the percentage of water by 24 per - 
cent. upon returning to normal diet, the water content is found 
to be higher than in the check. Abbe (1) has found that soaking 
seeds in water before planting accelerates germination but that 
germination is greatest in dry soil. 
Tower states that during hibernation, the cells take on a 
definite appearance due to loss of water, being shrunken and 
flattened. In all cells, the protoplasm takes on a colloidal 
granular appearance which is retained throughout the whole 
period. The nuclei have an extremely vegetative appearance— 
it often being impossible to show the presence of chromatin in 
cells which later will have abundant and active chromatic 
conditions. There is a twenty-seven per cent. loss of weight 
due to the emptying of the malphigian tubules of a red fluid and 
a three per cent. loss of weight due to the emptying of the 
alimentary canal that takes place just before hibernation in the 
potato beetle. 
Tower believes that this lowering in water content makes the 
maximum and minimum at which protoplasm can survive 
change in temperature in either direction, greater. Upon 
emergence from hibernation the reverse of the process of pre- 
paration for hibernation takes place—there is a rapid gain of 
