4 ORGANISED FLUIDS. 



The lymphatics of the upper and lower portions of the 

 body imbibe and carry along with them the various effete 

 matters and particles which are continually being given off by 

 the older solid constituents of our frame, and which are as 

 constantly undergoing a process of regeneration ; these they 

 redigest and reassimilate, into a fluid endowed with nutritive 

 properties, denominated lymph, and which is poured into the 

 thoracic duct. 



Those lymphatics, however, which arise on the surface of 

 the small intestines, and which, passing through the mesentery, 

 join the thoracic duct, have received a special appellation, 

 being called lacteals: this name has been bestowed upon them 

 on account of the milk-like appearance of the fluid which 

 they contain, viz. the chyle, a fluid derived from the digestion 

 of the various articles of food introduced into the stomach, 

 and which also is emptied into the thoracic duct. 



But the lacteals are not always filled with chyle ; they are 

 only to be found so when digestion has been fully accom- 

 plished ; when an animal is fasting, they, like other lymphatics, 

 contain merely lymph. 



The contents of the thoracic duct likewise vary : it never 

 contains pure chyle, but during digestion a fluid composed of 

 both chyle and lymph, the former predominating, and di- 

 gestion being completed, it is filled with lymph only. 



It follows therefore, that if we are desirous of ascertaining 

 the proper characters of chyle, our observations should not 

 be conducted on the fluid of the thoracic duct, but on that of 

 the lacteals themselves. It is a common error to regard and 

 to describe the contents of that duct, at all times, and under 

 all circumstances, as chyle, and it is one which has led to the 

 formation of some false conclusions. 



We will describe first the lymph, next the chyle, and 

 lastly the mingled fluid presented to us in the thoracic duct. 



The lymph is a transparent colourless liquid, exhibiting a 

 slightly alkaline reaction, and containing, according to the 

 analysis of Dr. G. O. Rees, 0*120 of fibrin, with merely a 

 trace of fatty matter. 



When collected in any quantity, and left to itself, the 

 lymph, like the chyle, separates into a solid and a fluid 



