676 GENERAL REVIEW OF THE NUTRITIVE PROCESSES. 



884. These considerations are of the highest importance in the treatment 

 of Disease ; the success of which will greatly depend upon the degree in 

 which the Physician follows the indications of Nature, instead of putting him- 

 self in antagonism to her course of operation. If we pay but a slight attention 

 to those phenomena which result from the introduction of poisons into the 

 system, we perceive that there is almost invariably an increased excretion of 

 some kind, which tends to eliminate them from the blood. Even where there 

 is no other obvious means for their removal, we can have little doubt that the 

 Respiratory function gives important aid in their separation ; when we keep 

 in view that from five to eight ounces of solid carbon, to say nothing of the 

 hydrogen, are thrown off from the lungs in the course of every twenty-four 

 hours. It is important to bear this circumstance in mind ; since it enables us 

 to understand how, if time be given, the system frees itself from such noxious 

 substances; and it points out the duty of the medical attendant to be rather 

 that of supporting the powers of the body by judiciously-devised means, and 

 of aiding in the elimination of the noxious matter by a copious supply of pure 

 air, than of interfering more actively to promote that which Nature is already 

 effecting in the most advantageous manner. We see the results of this ope- 

 ration in the case of Narcotic poisoning ; in which, if the Respiratory process 

 can be artificially kept up for a sufficient length of time, the powers of the 

 nervous system are gradually restored, even after what seemed to be their 

 complete and final cessation. There can be no doubt that, in like manner, 

 the system makes an effort to rid itself of other noxious substances, the pre- 

 sence of which in the blood results from morbid processes going on in the 

 body itself, and which, if retained, would produce the most serious conse- 

 quences. Thus a copious discharge of Lithic acid by the Urine will frequently 

 avert or curtail an attack of Gout. The copious acid perspirations, which 

 occur in certain forms of Rheumatism, are the means by which the Lactic acid 

 (which seems to be the materies morbi of this disease) is separated from the 

 blood. And there can be no doubt that an attack of Diarrho?a often prevents 

 more serious disease, by removing an unusual accumulation of the elements 

 of bile, or by eliminating an undue amount of putrescent matter, the continued 

 presence of which in the circulating fluid would induce the most serious dis- 

 orders in the nervous system. There can be no doubt that a due regulation 

 of the Excreting processes is one of the most important means, by which the 

 Physician can counteract the results of disordered actions in the system. They 

 may frequently require to be gently stimulated, in order to remove some mor- 

 bific elements from the blood. But it will be seldom that it will be desirable 

 to check them, even when apparently excessive, unless there be strong reason 

 to believe, that the excess proceeds from a disordered state of the organ itself, 

 produced by local causes only. 



2. Animal Heat. 



885. All the vital actions that have been considered in the preceding pages, 

 require a certain amount of Heat as a condition of their performance ; and in 

 the more elevated tribes of animals, in which (for the very purposes of their 

 creation) a high degree of constancy and regularity is required in these actions, 

 there is a provision within themselves for the maintenance of their temperature 

 at'a certain standard. We shall inquire, in the first place, into the amount of 

 Heat thus generated by Man ; and then into the sources of its production. 



880. Our present knowledge of the Temperature of the Human body under 

 different circumstances, is chiefly due to the investigations of Dr. J. Davy. 

 Much additional information may be expected, however, from inquiries which 



