3826 ANIMAL PHYSIOLOGY. 
rangement of its cells primarily or owing to obstruction to the 
outflow of bile leading to reabsorption by the liver, bile acids 
and bile pigments appear in the urine or may stain the tissues, 
indicating their presence in excess in the blood. 
This action of one gland (kidneys) for another is highly 
suggestive, and especially important to bear in mind in medical 
practice, both in treatment and prognosis. The chances of re- 
covery when only one excreting gland is diseased are much 
greater evidently than when several are involved. Such facts 
as we have cited show, moreover, that there are certain common 
fundamental principles underlying secretion everywhere —a 
statement which will be soon more fully illustrated. 
THe NATURE OF THE ACT OF SECRETION. 
We are now about to consider some investigations, more 
particularly their results, which are of extraordinary interest. 
The secreting cells of the salivary, the pancreatic glands, 
and the stomach have been studied by a combination of histo- 
logical and, more strictly, physiological methods, to which we 
shall now refer. Specimens of these glands, both before and 
after prolonged secretion, under stimulation of these nerves, 
were hardened, stained, and sections prepared. As was to be 
expected, the results were not entirely satisfactory under these 
methods; however, the pancreas of a living rabbit has been 
viewed with the microscope in its natural condition; and by 
this plan, especially when supplemented by the more involved 
and artificial method first referred to, results have been reached 
Fie. 277.—Portion of pancreas of rabbit (after Kiihne and Lea). A represents gland at rest; 
B, during secretion. 
which may be ranked among the greatest triumphs of modern 
physiology. 
