282 PHYSIOLOGICAL CHEMISTRY. 



CHYLE. 



During the digestion of fatty foods the lymph absorbed 

 from the intestinal walls contains numerous minute fat glob- 

 ules in the form of an emulsion. This portion of the lymph is 

 known as chyle and is carried along by the lacteals and finally 

 discharged into the lower part of the thoracic duct. 



In composition chyle differs from the lymph, from other 

 sources mainly in its fat content. In the periods when diges- 

 tion is not in progress the lacteal lymph is also clear. 



TRANSUDATIONS PROPER. 



The lymph has sometimes been considered a transudation 

 of the blood, but the term is now more commonly used to 

 describe the flow of liquid from the blood into certain cavities 

 of the body under pathological conditions. A transudation 

 proper is then a modified lymph and results often from an 

 imperfect elimination of water by the kidneys, or from some 

 disturbance in the circulation. Inflammatory transudations 

 are sometimes distinguished as exudations. 



For example, the pleural and peritoneal cavities contain but 

 little fluid. The serous surfaces are moist, but it would not be 

 possible to collect enough fluid substances for satisfactory an- 

 alysis under normal conditions. In the advanced stage of 

 pleurisy a considerable quantity of fluid collects in the pleural 

 cavity and its composition resembles that of the lymph, but it 

 is poorer in solids ordinarily. In some forms of acute peri- 

 tonitis a collection of similar fluid may take place in the peri- 

 toneal cavity and this may amount in bad cases to several 

 liters. 



The various forms of dropsy described by physicians are 

 essentially characterized by analogous transudations of serous 

 fluid without inflammation. Ascites, or dropsy of the ab- 

 domen, hydrocele, or dropsy of the testicle, and hydrothorax, 

 dropsy of the pleura, are illustrations. Some analyses are 

 given below, showing the general nature of the fluids collected 



