290 CHYLE. 



but these results, or rather the conclusions deducible from them, 

 differ considerably. This much, however, seems certain, that the 

 chyle is somewhat poorer in solid constituents after prolonged 

 fasting or where the food has been scanty, and that it then 

 contains a much smaller quantity of fat, so as to appear only slightly 

 turbid, but not milky. It has been generally maintained, that the 

 chyle becomes richer in fat after animal food, but this is only the 

 case where the nutriment has consisted of flesh, bones, milk, or 

 other fatty kinds of animal substances ; for Tiedemann and Gmelin 

 found that the chyle of dogs was rendered only faintly turbid, 

 when these animals were fed on albumen, fibrin, casein, and 

 gelatin. All observers agree in the opinion that the chyle becomes 

 milky and very rich in fat when the food has been of a fatty kind. 

 According to my observations, non- nitrogenous substances do not 

 produce any decided augmentation of fat in the chyle. No 

 definite conclusions can be drawn from the enquiries and opinions 

 of observers in reference to the influence exerted by the nature of 

 the food on the quantity of albumen and fibrin in the chyle, for 

 these substances owe their origin partly to transudation from the 

 blood in the mesenteric glands, and partly to the lymphatics of 

 the spleen, while moreover the chyle of the thoracic duct is the 

 only kind which has been accurately examined with a view of 

 ascertaining its quantitative relations. 



Nor can we attach any great weight to Millon's* elementary 

 analyses of the chyle and blood of dogs which had been fed on 

 different kinds of food ; at all events we cannot concur with that 

 observer, when he believes himself justified in concluding that 

 the special purpose of the lacteals is not the absorption of fats 

 only, but also of other nutrient substances in an equal degree. 



The chyle undergoes many alterations during its passage from 

 the lacteals of the intestines through the mesenteric glands to the 

 thoracic duct. We have already spoken of the diversity existing 

 in the morphological elements in the different parts of the 

 chyliferous system, in reference to the fibrin which, according to 

 Tiedemann and Gmelin, occurs in the smaller lacteals either in 

 very small quantities, or is entirely absent; we only know that 

 its quantity appears gradually to augment during the passage of the 

 chyle through the glands. A similar observation applies to the 

 albumen, which, according to the same observers, is conveyed in 

 large quantities to the chyle in the glands, so that this fluid appears 

 to increase in density in proportion as it approximates to the 

 receptaculum chyli. Fat is the only substance which seems to be 

 * Coropt, rend. T. 20, p. 817819. 



