ON EFFECT OF LOW TEMPERATURE ON COLD-BLOODED ANIMALS. 241 
The Lffect of Low Temperature on Cold-blooded Animals.— 
Report of the Committee, consisting of Professor SWALE 
ViNcENT (Chairman) and Mr. A. T. CAMERON (Secretary). 
(Drawn up by the Secretary.) 
Mr. A. T. Camexron has continued the experiments of Cameron and 
Brownlee on frogs communicated in the last report, and has arrived at 
the following conclusions :— 
(1) The death-temperature of R. pipiens from cold is — 1259 + 
mise C. . 
(2) There is no climatic adaptation, nor any periodic adaptation due 
to hibernation, in RA. pipiens. 
(3) The cause of death is a specific temperature effect on the co- 
ordinating centres in the central nervous system. Those controlling 
lung-respiration may be specially concerned. 
(4) Frogs surviving degrees of cold such as those occurring during a 
Manitoban winter do so below the surface, near the margin of springs, 
and are themselves never subject to temperatures below the freezing- 
point of water. 
(5) There seems to be a slight variation in the death-temperature 
from cold, of different species of frogs, amounting to some tenths 
of a degree Centigrade. 
(6) Frogs heated rapidly to normal room-temperature from a tem- 
perature just below the freezing-point of their body-fluids (and not itself 
capable of causing death) are thrown into a peculiar hypersensitive 
condition, in which cessation of lung-breathing takes place for long 
periods. 
These results are deduced from experiments with R. pipiens from 
Manitoba, Minnesota, and Illinois, with R. clamitans from Minnesota, 
and with R. sphenocephala from C. Carolina. The experimental details 
will be published elsewhere. The Committee do not wish to be re- 
appointed. 
Miners’ Nystagmus.—Interim Report of the Committee, con- 
sisting of Professor J. H. MurrHeap (Chairman), Dr. T. G. 
MalTLaANp (Secretary), Dr. J. JAMESON Evans, and Dr. 
C. 8. Mysrs, appointed to investigate the Physiological and 
Psychological Factors in the Production of Miners’ 
Nystagmus. 
Factors concerned: (a) Internal; central and peripheral. (b) External. 
Two features have long been admitted to be provoking agencies in the 
production of miners’ nystagmus—an external factor, defective lighting, 
and an internal or peripheral factor, viz., muscular strain. The former, 
defective lighting, is found to be the more important, and our examina- 
tion led us to conclude that where this factor is in greatest evidence 
there we find the greatest incidence of cases. Miners’ nystagmus is 
a disease limited practically to coal-mining, and, further, it is associated 
with the use of lamps of small illuminating power, such as the Davy 
1914. R 
