214 ANNUAL OF SCIENTIFIC DISCOVERY. 



the whole amount of that which is produced in a quiescent state ; but 

 the whole amount of decomposition in the living body is five times as 

 great. Of these five quantities one quantity is spent for mechanical 

 work, and four-fifths remain in the form of heat. The production of 

 heat in the body while doing great mechanical work is notorious, and 

 hence we see how much the decompositions in the body are increased 

 thereby. The human body, says Helmboltz, is a better mechanical 

 machine than the steam-engine, only its fuel is more expensive, for, if 

 we take any thermo-dynamic engine, we find that the greatest amount 

 of mechanical work which can be gained is an eighth part of the 

 equivalent of the chemical force generated by the combustion of the 

 fuel, the remaining seven-eighths being lost in the form of heat. In 

 the human body, on the other hand, one-fifth of the chemical force is 

 spent in doing mechanical work, the other four-fifths remaining as 

 heat.- London Chemist, Henry Noad. 



ANIMAL HEAT. 



But few subjects have ever proved more rebellious to a satisfactory 

 elucidation and explanation than the source of animal heat. The 

 most eminent physiologists of past as well as of the present age have 

 alike exhausted their ingenuity without satisfactory results. Baron 

 Liebig, several years since, gave an explanation, that, from its sim- 

 plicity and plausibility, acquired pretty general favor ; a few, how- 

 ever, were not satisfied with this theory, and their objections are 

 likely to demolish it altogether. Prof. Draper asserts that " in every 

 instance the production of animal heat is due to oxidation taking 

 place in the economy." (Draper's Physiology, p. 182.) But where 

 oxidation exists, there exists also deoxidation, and the latter is as 

 much a cooling as the former is a heating process. We have not 

 space nor inclination to review the several theories that have been 

 proposed to account for the production of animal heat. It may be 

 known to some of our readers that Prof. Bennett Dowler, of New 

 Orleans, has for many years entertained peculiar views upon this sub- 

 ject. In the New Orleans Medical and Surgical Journal, for May, 

 he has an article upon the subject, detailing many experiments per- 

 formed by himself bearing upon his views. 



Prof. Draper affirms that " heat depends on the power of the pul- 

 monary engine," and says " the absolute temperature will depend 

 on the respiratory condition." Prof. Dowler opposes this idea, be- 

 lieving that annual heat is not dependent upon pulmonary combus- 

 tion. We think he has the best of the argument. We have not the 

 space to quote his opinions, but will, as concisely as possible, allude 

 to a few of his more important arguments. 



On examining the body after death, he finds the lungs lower in 

 temperature than many other portions of the body ; and, in many 

 instances, he has found the heat of the body absolutely to rise for a 

 little time after respiration ceases. In pneumonia and consumption, 

 though in the former the office of the lungs is obstructed, and in the 

 latter much of the lung substance may be destroyed, the heat of the 

 body is usually, and perhaps always, above the normal standard. In 

 sunstroke the respiratory act is very imperfectly performed, and yet 

 it " is the hottest of all diseases." 



