818 



SCIENCE 



[N. S. Vol. XLII. No. 1093 



plasmic tissue determines the height of the 

 metabolism. However, in the search for a 

 standard upon which to calculate what 

 would be the normal heat production of a 

 man suffering from disease it is obviously 

 impossible to measure the mass of active 

 protoplasmic tissue. It is, therefore, most 

 fortunate that the unit of surface area 

 eliminates the same amount of heat in the 

 normal adult within ten per cent, of a de- 

 termined average. 



The reason for this is not clear, but the 

 fact is established. It is known that a reg- 

 ulating mechanism maintains the body 

 temperature at a fixed point, though the 

 reason for this is also undetermined. 



The figures given hold true for the adult 

 but are subject to variations due to age. 



Murlin has pointed out that the new- 

 born baby has a distinctly lower metabol- 

 ism than normal and that this rapidly rises 

 during the first year to a standard above 

 the normal. It should be remembered in 

 the first place, that the newly born may be 

 considered in the light of an internal or- 

 gan which has been protected from exter- 

 nal stimuli. This is indicated by the work 

 of Murlin upon the pregnant dog and from 

 that of Murlin and Carpenter upon the 

 human mother. The increase in heat pro- 

 duction during the first months of the in- 

 fant's life may be due to the union of the 

 muscles with meduUated nerve fibers. 

 Furthermore, one finds on analysis that 

 there is 24 per cent, of muscle tissue in the 

 newly born baby as against 42 per cent, or 

 nearly double that quantity in the adult. 

 These proportions are reversed as regards 

 glandular tissue, there being 47 per cent, 

 of this tissue in the newborn and only 24 

 per cent, in the adult. It is this prepond- 

 erance of glandular tissue in early life that 

 may be the cause of the prevalence of the 

 higher metabolism during the early period 

 of growth. Du Bois has found that in a 



number of boys just before puberty the 

 heat production is 25 per cent, above the 

 normal and it is interesting to query 

 whether this be due to glandular activity. 



With the approach of old age the meta- 

 bolism falls about ten per cent. ; there is no 

 longer quite the same intensity of oxida- 

 tion as at the height of a man's virility. 



In conditions of disease, as in those of 

 health, the same materials, such as protein, 

 fat and carbohydrate are oxidized and in 

 the normal fashion, and they produce heat 

 after the normal manner. The disease of 

 diabetes presents a striking exception, as 

 sugar may here remain unoxidized. In 

 general, one may say that the intensity of 

 the metabolism processes are little affected 

 in many diseased conditions. In diabetes 

 the heat production does not rise appre- 

 ciably above the normal. The calorimeter 

 in the hands of Du Bois and his fellow 

 worker has shown that in severe anemias 

 and in heart disease involving dyspnea, the 

 heat production may increase. This is very 

 probably due to the stimulus of lactic acid, 

 a similar phenomenon being witnessed in a 

 dog poisoned Avith phosphorus. In a typi- 

 cal fever such as typhoid the heat produc- 

 tion may increase between 40 to 50 per 

 cent, and in severe eases of exophthalmic 

 goiter it rises to between 75 to 100 per 

 cent, above the normal. It is fortunate 

 that the ingestion of food which in the 

 normal individual causes an increase in 

 heat production, does not abnormally stim- 

 ulate the fires of metabolism in these pa- 

 tients already suffering from intensified 

 oxidation processes. 



The inner process of heat production in- 

 volves the interplay between the living 

 cells of the body and the nutrient constitu- 

 ents of the fluids which bathe them. It has 

 been known since the time of Lavoisier that 

 the ingestion of food results in an in- 

 crease in metabolism. In the presence of 



