EVOLUTION OF HEAT, LIGHT, AND ELECTRICITY. 527 



in the minute; after this it gradually returned to the normal in the course 

 of the day. During the febrile state the urine contained albumen. There 

 can be no doubt whatever, that imperfect action of the Cutaneous glanduhe, 

 consequent upon inactive habits of life and want of ablution, is a very fre- 

 quent source of disorder of the general system ; occasioning the accumula- 

 tion of that decomposing organic matter in the blood, which it is the special 

 office of these glanduke to eliminate. Hence the due maintenance of health 

 requires that this excretion should be promoted by the use of the natural 

 and appropriate means just referred to; and this is the more necessary, when 

 from any cause the function of the kidneys is imperfectly performed. There 

 are many diseased states, moreover, in which there appears to be a special 

 determination of the materies inorbi to the Skin; and in which, therefore, 

 the use of means that promote the cutaneous excretion constitutes the most 

 efficient method of eliminating it from the blood. 1 



CHAPTER XII. 



EVOLUTION OF HEAT, LIGHT, AND ELECTRICITY. 



1. General Considerations. 



423. THE series of Nutritive operations which has now been passed in 

 review has been shown to consist in the continual appropriation, by the 

 Animal organism, of certain "organic compounds" or "alimentary mate- 

 rials," which have been generated for its use by Plants; and in the con- 

 stant restoration of their elements to the Inorganic world, either in the very 

 same forms of combination in which they originally existed there, or as 

 products of incipient decay, by whose further decomposition those simple 

 binary compounds will be reproduced. And thus, so far as the material 

 components of the Organic Creation are concerned, the agency of Vegetable 

 life is employed in withdrawing them from the Mineral world, and that of 

 Animal life in returning them to it, after they have served their purpose in 

 the living structure. But if we examine into the source of those active 

 powers or " forces," on whose operation every change, no less in the organ- 

 ized body, than in what is commonly designated as " inert " matter, is de- 

 pendent, we shall find that they are all traceable to the solar radiations. It 

 is by the action of the Light and Heat of the Sun upon the Vegetable germ, 

 that it is enabled to exercise its wonderful transforming capacity, whereby it 

 extracts carbon, hydrogen, nitrogen, and oxygen, from the carbonic acid, water, 

 and ammonia furnished by the atmosphere or the soil ; and that it converts 

 these into the albuminous, saccharine, and oleaginous compounds, which 

 are the destined food of Animals. And it is under the influence of Heat 

 chiefly derived from the same source, that the greater number of tribes of 



, 



1 The practical value of active diaphoresis in many febrile diseases, is well under- 

 stood by the native practitioners among the Negroes ol the Guinea Coast; who, accord- 

 ing to Dr. Daniell (Medical Topography and Native Diseases of the Gulf of Guinea, 

 pp. 119-20), make use of it most successfully in the treatment of ailynamic remittent 

 fevers. Dr. Daniell states that having himself had abundant experience, of its effi- 

 cacy, he has no doubt of its superiority in these cases to the ordinary practice of 

 venesection, saline purgatives, large doses of calomel, etc. And he has repeatedly 

 stated that one great secret of preserving health in tropical climates, lies in due atten- 

 tion to the cutaneous functions. 



