THE BLOOD. 87 



and were relieved either by spontaneous hemorrhages, or by 

 bloodletting, is it not probable that, to whatever purpose (see 

 Note LX), the oil is applied in the body after it is reabsorbed 

 from the cellular membrane, in these patients it had been re- 

 absorbed faster than it was applied, and by that means was 

 accumulated in their blood-vessels ? This conjecture seems to 

 be confirmed, from considering that in most of these cases the 

 people were inclined to corpulency, and that two of them 

 laboured under a stoppage of a natural evacuation. 1 



Another conclusion which these observations lead us to is, 

 that since the chyle of the birds (LIX) which I dissected was 

 not white, but transparent, at whatever time after eating it was 

 examined, it follows, that the fat (in these animals at least) is 

 not merely the oily part of the chyle or of the food, but is a 

 new substance, or a new combination of the principles or ele- 

 ments, which is made probably in the secretory organs of the 

 adipose membrane ; the form of oil being made use of by na- 

 ture in preference to any other for the nutritious substance of 

 the body, from its being the least liable to putrefaction, and 

 from its containing the greatest quantity of nourishment in the 

 least bulk. This circumstance was clearly proved by my valu- 

 able and ingenious friend the late Dr. Stark (LX), who, in a 



1 Although it appears probable that the whiteness of the serum in the above- 

 mentioned cases was not owing to the chyle, yet I would not conclude that the chyle 

 does not in the human subject occasionally colour the serum. We frequently observe 

 the serum of such people as are bled a few hours after a meal, a little turbid, like 

 whey, which I believe may be owing to the chyle. But if the milk-like serum was 

 occasioned by a full meal, it is likely we should oftener see it than we do. 



(LIX.) The chyme of birds differs very little from that of mammalia. 

 In geese fed exclusively on barley, in many wild finches, and in pigeons fed 

 on nothing but peas, I found a much greater proportion of fatty matter 

 in the chyme than in the food. An observation, communicated to me 

 by Dr. Davy, is still more conclusive : in the chyme of a pheasant he 

 found oily matter, which he could not detect in the food, consisting of 

 pilewort, in its crop. The subject is interesting in connexion with the 

 contending views of Liebig, Boussingault, and Dumas, a on the question 

 of the formation of fat in animals. The chyle of birds, as Dr. Davy 

 suggests to me, may perhaps enter the circulation by the veins rather 

 than by the colourless lymphatics. 



(LX.) Dr. William Stark' s works, consisting of clinical and anatomical 



* Mr. Paget's Reports, Br. & For. Med. Rev. xvii, 260 ; xix, 564. 



