296 ANATOMY AND PHYSIOLOGY FOR NURSES 



to prevent the obstruction they would otherwise give 

 rise to. 



These materials may be compared to the ashes of a 

 furnace they are the result of combustion or oxida- 

 tion. They are absorbed from the circulation by means, 

 principally, of the sudorific glands, and carried off by what 

 is called cutaneous transpiration, or perspiration. Mucous 

 surfaces, especially those of the alimentary canal, also 

 secrete from the circulation pecant or exhausted materials 

 and eliminate them in the dejecta. 



Pulmonary transpiration corresponds to the chimney 

 of the furnace it gives off the smoke or carbon dioxid 

 and other consumed material. The kidneys remove 

 saline and acrid products of the tissue metamorphosis 

 that are similar to, but much more irritating than, the 

 perspirable fluid. 



NUTRITION 



The processes of nutrition and the necessity for the 

 continued supply of material have already been dwelt 

 upon. The source of nutrition, as has been stated* 

 elsewhere, lies in food. A question regarding nutrition 

 that still remains unanswered is, What is the precise 

 modus operandi of nutrition? 



By the action of the various acids, salts, and other 

 secreted products of animal combustion, which are fur- 

 nished by the glandular viscera, as the liver, pancreas, and 

 the lymphatics, the food, or ingesta, becomes admixed 

 with these secretions in the process of digestion and the 

 course of the circulation, and becomes still better fitted for 

 ready combination with the substances of the tissues. 



There is no force required for this nutrition, except 

 the affinity that the several substances have for one an- 

 other. It must, however, be understood that all these 

 processes go on under vital direction of these affinities. 



