THE BLOOD. 89 



that fluid then perhaps necessary for the use of the body. In 

 order to clear up this point, I thought it would be a satisfactory 

 experiment to compare the serum of the blood of animals at 

 different periods after feeding them. For if the reabsorption 

 of the oil was merely to make up for the want of other food, 

 or if the serum was white merely from a greater quantity of 

 oil being taken up in order to supply the wants of the body, 

 then the serum ought to be whitest in the animal kept longest 

 without food, or whose body was most in want. And as I had 

 found that geese had very commonly this white serum, though 

 their chyle was transparent, I chose to make the experiment on 

 them. I therefore took two of them that were very hungry, 

 and feeding both of them with oats, one I killed four hours 

 after, when I knew a part of the oats were undigested ; and 

 upon examining the blood, I found the serum whitish, and full 

 of small globules ; on its being suffered to stand a little time, 

 the white part ascended to the surface like a cream. The 

 other was killed forty-eight hours after eating, when its stomach 

 was found empty, and the serum of its blood quite trans- 

 parent, and without any cream rising to the surface, or any ap- 

 pearance of small globules, when examined with the microscope. 

 Now this experiment seemed to me decisive, and to point out 

 clearly that the whiteness of the serum was not occasioned 

 merely by the body being in want of food, and therefore draw- 

 ing the oil from its magazines ; because here the animal most 

 in want of food had its serum least white ; but was occasioned 

 by the fat being reabsorbed faster than it was used (from its 

 place being supplied by the fresh chyle) and thence was accu- 

 mulated in the blood-vessels, so as to give whiteness to the 

 serum. And from the same observation it likewise appears 

 probable, that the great reabsorption, and the accumulation 

 of the fat in the vessels of the plethoric patients above men- 

 tioned, was the cause of their want of appetite, and of their 

 other complaints, and not the effect of them. 



May not therefore a too great reabsorption of the fat, and 

 its accumulation in the blood-vessels, be now admitted as the 

 cause of one species of a plethora ? 



And may it not likewise be useful in some complaints of the 

 stomach to attend to the whiteness of the serum ? For although 



