198 
POPULAR SCIENCE REYIEW. 
investigated tlie action of the salts of sodium, potassium, and rubidium ; 
and who showed (1) that sodium salts maybe introduced into the blood 
in very large doses without producing serious results ; (2) that the salts 
of potassium similarly introduced are extremely poisonous, and have an 
immediate toxic effect, even in small doses. M. Bernard’s experiments show 
that the potassium salts exert their action on the muscular tissue, and that 
death caused by injection of them into the blood is the result of cessa- 
tion of heart action, due to arrest of the respiratory movements. MM. 
Jolyet and Cahours record numerous experiments on dogs, which show 
conclusively that the potassium salt has a very seriously poisonous in- 
fluence on the heart, causing an immense increase in its actions. Similar 
experiments with sulphate of sodium prove (1) that this salt has no pur- 
gative effect in this way ; and (2) that by diminishing the coagulability 
and plasticity of the blood, it promotes haemorrhages, and retards cicatriza- 
tion. 
Temim'aturc of the Body in Health. — Dr. Sydney Binger gives an abstract 
of a paper lately laid before the Koyal Society on this subject. He gives 
the results of the experiments made by himself and the late A. P. Stewart. 
The following are the conclusions. The average maximum temperature of 
the day in persons mider 25 years of age is 99°T Fahr. ; of those over 40, 
98°'8 Fahr. There occurs a diurnal variation of the temperature, the 
highest point of which is maintained between the hours of 9 a.m. and 6 p.m. 
At about the last-named hour the temperature slowly and continuously 
falls, till, between 11 p.m. and 1 a.m., the maximum depression is reached. 
At about 3 A.M. it again rises, and reaches very nearly its highest point by 
9 A.M. The diurnal variation in persons under 25 amounts, on an average, 
to 2*^’2 Fahr. ; but in persons between 40 and 50 it is veiy small, the 
average being not greater than 0°-87 Fahr. ; nay, on some days no variation 
whatever happens. In these elderly people the temperature still further 
differs from that of young persons ; for in the former the diurnal fall occurs 
at any hour, and not, as is the case wdth young persons, during the hours of 
night. Concerning the influence of food on the temperature of the body, 
the authors have concluded that none of the diurnal variations are in any 
way caused by the food we eat. The experiments to prove this conclusion 
are very numerous. Some were made with the breakfast, others with the 
dinner and tea; but all point to the conclusion just stated. This important 
question is very fully discussed in the section devoted to it. By cold baths 
both the surface of the body and the deep parts were lowered in tempera- 
ture. The temperature of the surface was in some instances reduced to 
88° Fahr. ; but the heat so soon returned to all parts as to show that the 
cold bath is of very little use as a refrigerator of the body. The cold bath 
produced no alteration in the time or amount of the diurnal variation. This 
began at the same hour, and reached the same amoun t ns on those days 
wlien no bath was taken. By hot-water or vapour baths the heat of the 
body could be raised very considerably. Thu.s, on some occasions, when 
using the general hot bath, the temperature under the tongue was noted to 
be Ixjtween 103° and 104° Fahr. — a fever temperature. The body being 
heated considerably above the point at which combustion could maintain it, 
t was then shown with what rapidity heat may be lost, simply by radiation 
