sin 1 ERING 449 



have been covered with a layer of inipcnetrablc varnish. It is 

 alleged that, at the enthronement of Pope Leo X., a boy was 

 gilded to represent an angel. Before the ceremony was finished 

 the boy, despite the efforts of Leonardo da Vinci and other 

 physicians, had died. That excessive heat loss was the cause of 

 this accident is proved by the experiments of Valentin. He 

 showed that, under similar circumstances, the carbon-dioxide 

 output of the subject was reduced to about one-sixth of the normal, 

 i.e. metabolism was at a low ebb. If the animal were kept 

 normally warm, the carbon-dioxide output retin^ned to a normal 

 figure. On the other hand, Senator states that the human body 

 can be covered for 8 to 10 days with an impenetrable layer of 

 varnish without producing any disturbance of metabolism. He 

 avers that, in those cases where vasodilatation occurred, some 

 toxic substance must be absorbed from the varnish. 



Alcohol produces vasodilatation — an increased cooling surface. That 

 is, this drug, because it causes more warm blood to come to the surface, 

 gives rise to a sensation of cutaneous warmth while at the same time materially 

 aiding in the depletion of the body's store of heat. 



B. Chemical Regulation — Curative. (Usually predominant below^ 

 26° C. and over 40° C.) 



These mechanisms come into play to replace heat which has 

 been lost or when the surroundings are warm to prevent the body 

 from liberating heat from potential energy. 



(a) Voluntary or involuntary work. We have already seen 

 that work causes the liberation of heat and we have discussed 

 the reason for this. Shivering, or involuntary work is a reflex 

 act which occurs in any person of normal muscular tone when the 

 skin temperature is allowed to drop below a certain value. 

 Anything which will prevent muscle from responding to this 

 stimulus will do away with this curative heat production, e.g. 

 curari, alcohol, etc. Young animals which have little muscular 

 development are, obviously, unable to keep themselves warm 

 by exercise and have to be carefully protected against inidue 

 heat loss. 



{b) Increased muscular work ultimately leads to increased 

 catabolism of food material and so, indirectly, to an increase in the 

 quantity of heat liberated. Over and above this amount, however, 

 the result of exposure to excessive cold may be combated by the 

 ingestion of foods having a high energy value. Cold blood 

 augments the sugar consumption of the heart-lung preparation, 

 while warm blood has the opposite effect. Natives of the colder 

 climates introduce much fatty matter into their diets, while 



B. S'J 



