416 
ON INCREMENT OF ANIMAL HEAT. 
feet conductive power of the subcutaneous layer of fat, a more 
rapid increment of heat. For this reason children who have 
a thick layer of adipose matter run most risk in acute inflam¬ 
matory disorders and in exanthematous diseases; indeed, in 
these the temperature of the body may be raised to the point 
of dissolving the fatty matter itself, so that the blood may 
have free oily substance floating in it. As I have already 
stated in a previous lecture, free fat is often found surround¬ 
ing fibrinous separations in young children wdio have died 
from acute inflammatory disease. 
6. Again, let me urge the importance of watching the in¬ 
fluence of season on the ihermometrical readings of the animal 
body. In sound states of health there will always be a slight 
increase of mean temperature of the body during the heat of 
summer, and a decrease of the mean temperature during the 
cold of winter. It is true that nature does much to equalise ; 
that the free action of the skin and lungs in the hot, and the 
slow action of the same organs in the cold months, specially, 
tends to equalisation. But a difference ranging from one 
degree and a half to tw^o degrees Fahrenheit must still be al¬ 
lowed, and it must be borne in mind that an extreme increase 
of animal temperature in the cold months is a much more 
serious matter than the same increase in hot months of the 
year. Further, there are some months which are specially 
critical in these respects; there are months when animal 
increase is enormous. Thus the late Mr. Milner, of Wake¬ 
field, in a research the most severe and exact of its kind I 
ever remember to have read, discovered that in the month of 
March there is a loss of weight in the body equal to 0 9o, 
and in August an increase equal to 0*70, the loss commencing 
in October and going on to April, and the gain commencing 
in May and continuing until August, the great loss and the 
great gain being equally sudden and determinate at the close 
of their periods— i. e. in March and in August. These same 
periods it is of moment to remember in relation to fluctuations 
of animal temperature. An unusual rise of temperature 
during the present month, for instance, when a process of 
waste is naturally progressing, is specially dangerous; it 
means increase of waste with diminution of reserve power. 
7. Lastly, when we turn from man to different classes of 
animals, it is essential to bear in mind the differences of 
arrangement for the conduction of heat from the outer surface 
of the body. An animal thickly and persistently covered 
with fur, or wool, or feathers, and which has an imperfect 
cutaneous mechanism for disposal of water by evaporation, 
will, ccEteris paribus, have a higher temperature than another 
