CHARACTERS AND COMPOSITION OF CHYLE. ' 525 



merits, it is impossible to form an exact appreciation either of their form or 

 their dimensions. They seem, however, to be generally spherical; and their 

 diameter may be estimated at between 1 -36,000th and 1 -24,000th of an inch. 

 Their chemical nature is as yet uncertain : they are remarkable for their un- 

 changeableness, when subjected to the action of numerous re-agents; which 

 quickly affect the proper Chyle-corpuscles; and they are readily soluble in 

 Ether, the addition of which causes the whole molecular base instantly to dis- 

 appear, not a particle of it remaining; whence it may be inferred that they 

 consist of oily or fatty matter. The milky colour, which the serum of blood 

 sometimes exhibits, is due to an admixture of this molecular base with the 

 circulating fluid ; it is most common in young animals that are suckling ; but 

 it is not uncommon in adults, and is not to be attributed to an absorption of 

 milk into the chyle, as the physical properties of the two are quite different. 

 (See 697, e.) 



693. During the passage of the Chyle through the absorbents on the intes- 

 tinal edge of the Mesentery, towards the Mesenteric Glands, its character 

 changes in several important particulars. The presence of Fibrine begins to 

 manifest itself, by the slight coagulability of the fluid when withdrawn from 

 the vessels ; and while this ingredient increases, the Albumen and the Oil- 

 globules gradually diminish in amount. The Chyle drawn from the neigh- 

 bourhood of the mesenteric glands exhibits the Corpuscles regarded as cha- 

 racteristic of that fluid ; these are peculiarly abundant in the fluid drawn from 

 the glands themselves ; and they are constantly found in it, through its whole 

 subsequent course. The Chyle-corpuscles are much larger than the mole- 

 cules just described, and an examination of their character presents no diffi- 

 culty. Their diameter varies from 1-71 10th to 1 -2600th of an inch ; the 

 average being about l-4600th. They are usually minutely granulated on the 

 surface, seldom exhibiting any nuclei, even when treated with acetic acid ; but 

 sometimes three or four central particles may be distinguished within them. 

 During the passage of the Chyle through the mesenteric glands, a further 

 increase in the proportion of Fibrine takes place ; and the resemblance of 

 the fluid to Blood becomes more apparent. The Chyle drawn from the vessels 

 intermediate between these and the central duct, possesses a pale reddish- 

 yellow colour; and, when allowed to stand for a time, undergoes a regular 

 coagulation, separating into clot and serum. The former is a consistent gela- 

 tinous mass, which, when examined with the microscope, is found to include 

 the Chyle-corpuscles, each of them being surrounded by a delicate film of 

 oil: the Fibrine of which it is principally composed, differs remarkably from 

 that of the blood, in its inferior tendency to putrefaction ; whence it may be 

 inferred that it has not yet undergone its complete vitalization. The serum 

 contains the Albumen and Salts in solution, arid a proportion of the Chyle- 

 corpuscles suspended in it. It is curious, however, that considerable differ- 

 ences in the perfection of the coagulation, and in its duration, should present 

 themselves in different experiments. Sometimes the chyle sets into a jelly- 

 like mass, which, without any separation into coagulum and serum, liquefies 

 again at the end of half an hour, and remains in this state. This change takes 

 place in the true coagulum also, if it be kept moist for a sufficient length of 

 time. The Chyle from the Receptaculum and Thoracic Duct coagulates 

 quickly, often almost instantaneously; and few or none of the corpuscles re- 

 main in the serum. It is to be remembered that the Lacteals are the Lym- 

 phatics of the intestinal walls and mesentery ; performing that function of 

 Interstitial Absorption which is elsewhere accomplished by vessels that are 

 not concerned in the introduction of alimentary substances from without. 

 During the intervals of digestion, they contain a fluid which is in all respects 

 conformable to the Lymph of the Lymphatic trunks. 



