182 ANATOMY AND PHYSIOLOGY. 



veins is also often obstructed, and this very generally gives rise to 

 the liver complaint and dropsy. 



What has been said must suffice in regard to the larger glands ; 

 smaller ones are scattered in almost every part of the body. The 

 whole extent of the intestinal canal, and of the skin, is found to 

 be studded with bodies having a glandular structure, and producing 

 secretions. 



Some secretions are evidently produced only in particular emer- 

 gencies, as we see with the increased secretion of bony matter when 

 a limb is broken ; other secretions are uncommon in their nature, 

 as in the case of such fishes as the torpedo or of the firefly, the 

 former of which can produce at pleasure powerful electrical dis- 

 charges, and the latter a substance that gives out light ; while in 

 other instances, again, secretions become unusual in their situation, 

 or of a morbid kind. Of a secretion unusual in its situation, a 

 curious instance occurred some years ago in France. A woman 

 who was suckling had the secretion of milk transferred from her 

 breasts to one of her lower extremities, from which her child con- 

 tinued to be supplied. Of morbid secretions we have examples in 

 ossification of the valves of the heart, in consumption, in cancerous, 

 brainy, and other tumors, and, unfortunately, in too many other 

 cases. 



The secretions are much influenced by our mental states. Every 

 one has felt the flow of saliva increased from savory odors, or the 

 flow of tears from distressing feelings. A cheerful state of mind is 

 peculiarly favorable to the proper performance of the function of 

 secretion ; and we therefore learn how important it is to avoid such 

 things as distract, or agitate, or harass us ; and yet how un- 

 avoidable ! 



As to the agent which produces or directs the different secretions, 

 we have no very accurate information. In one instance, at least, 

 Dr. W. Philip found that its place could be supplied by galvanism. 

 He cut the principal nerves going to the stomach, and the secretion 

 of gastric juice was completely stopped ; but the secretion was 

 restored when a galvanic pile was made to communicate with the 

 lower extremities of the nerves. Of late years it has been dis- 

 covered that the operations of galvanism are much more various 

 and subtle than was formerly supposed, and it therefore seems not 

 unreasonable to conjecture that its agency may be important also in 

 secretion. 



