PAWLOW'S RESEARCHES ON THE PHYSIO- 

 LOGY OF SECRETION. 



THE researches of Pawlow, of which I wish to give a 

 short account in the following pages, are worthy of 

 attention, not only by reason of their importance in filling a 

 much-felt void in our physiological knowledge, but also be- 

 cause they embody a new departure in physiological method. 



It might have been thought, when Ludwig, in 185 1, dis- 

 covered the innervation of the salivary glands, and showed 

 that, by stimulation of certain nerves, a secretion of saliva 

 could be invariably invoked, that our knowledge of the 

 innervation of the other glands of the body would rapidly 

 have been completed. Yet up to the date of Pawlow's re- 

 searches the two most important secretions which are poured 

 into the alimentary canal, i.e., the pancreatic and gastric juices, 

 although the subjects of numerous investigations, had foiled 

 all attempts to discover the nervous impulses which control 

 their production. 



This want of success of the various experimenters is not 

 to be wondered at when we consider the conditions under 

 which so-called "physiological" experiments are usually 

 carried out. It is a matter of common experience that the 

 digestion of food, i.e., the secretion of active digestive juices, 

 is intimately dependent on the well-being, mental or physical, 

 of the animal, and is absolutely checked by abnormal con- 

 ditions, such as fright, pain, administration of narcotics 

 (opium, chloroform, alcohol, etc.). Now in most experi- 

 ments the dog or other animal employed is first poisoned 

 with a large dose of morphia, is rendered fully anaesthetic 

 with chloroform or ether, and in many cases is also poisoned 

 with curare. If anaesthetics are omitted the animal is tied 

 down and subjected to an extremely painful operation. It 

 is under circumstances such as these that experiments on 

 the innervation of the gastric and pancreatic glands have 

 failed to have any definite results. 



One other difficulty in experimenting on these glands 



