
No. 425.] NOTES AND LITERATURE. 403 
of color aberrations in butterflies. He also suggests that further study 
of these effects may explain why so many moths are nocturnal, while 
the butterflies are diurnal. Some experiments on the influence of 
respiration showed that Deilephila at 29.4° C. atmospheric tempera- 
ture could raise its body temperature through at least 3° C. by 
means of breathing alone. 
The second and more important portion of Bachmetjew’s paper 
deals with the vital extremes of temperature. It is divided into two 
sections, one dealing with the maximum, the other with the minimum 
temperature. The vital maximum is the highest temperature at which 
an insect is able to live. Experiments on Saturnia pyri showed that 
the insect becomes very restless at a temperature of about 39° C. 
and dies when the body reaches a temperature of 46^ C. This is 
also very near the lethal temperature for plants (Sachs and Schultze). 
This lethal temperature, however, depends on a number of factors. 
In general, it may be said that if the insect at high temperature first, 
has not been exhausted, Z^, has been artificially fed; second, is not 
desiccated, że., is in a sufficiently moist atmosphere; and third, pre- 
sents the same conductivity to heat and the same body size for a 
given species, — its life will depend only on the coagulation or non- 
coagulation of its body fluids. Hence, the vital maximum is only 
another expression for the coagulation point of the body fluids. And 
if one knew the amount of water in the insect's albumins, especially 
of those albumins essential to life, the question of the vital maximum 
would resolve itself merely into a determination of the amount of 
water. 
Bachmetjew's study of the vital minimum, Ze, the lowest tempera- 
ture at which an insect can live, brought out some startling results. 
He found from experiments on a great number of insects that 
different species died at very different temperatures. But his most 
interesting results refer to the critical point, which is the temperature 
to which the fluids of the insect may be undercooled before they 
begin to congeal and then suddenly rise in temperature till the nor- 
mal congealing point is reached.  Bachmetjew points out the resem- 
blance of this phenomenon to the well-known undercooling of water, 
. which can be cooled to — 25° C. without freezing, but at once rises 
to o? C. to freeze. Bachmetjew discovered the undercooling of the 
body fluids of insects by accident in an experiment on Saturnia 
pyri 9. The insect was cooled to — 9.4^ C., whereupon within a 
minute's time the temperature bounded up to — 1.4° C., the normal 
congealing point of the body fluids, and then remained constant for 
