122 PHYSIOLOGICAL CHEMISTRY. 



amount of albumin in the PERICARDIAL, PLEURAL, and PERITONEAL 

 FLUIDS is considerably greater than in those fluids which are found 

 in the ARACHNOID MEMBRANE, in the SUB-CUTANEOUS TISSUES, or in 

 the AQUEOUS HUMOR. The condition of the blood also greatly 

 affects the transudations, for in hydraemia the amount of albumin 

 in the transudation is very small. With the increase of the age of 

 a transudation, of a hydrocele fluid for instance, the quantity of 

 albumin is increased, probably by resorption of water, and indeed 

 exceptional cases may occur in which the amount of albumin, with- 

 out any previous bleeding, is greater than in the blood-serum. 

 It is natural to suppose that the state of the circulation and the 

 pressure must have an influence on the quantity and composition 

 of the transudation even though their action is little known. By 

 increasing the vein-pressure SENATOR caused an increase in the 

 quantity of transudation and the amount of albumin contained 

 therein, while the amount of salts was not essentially changed. Of 

 the variation in the amount of albumin by simple arterial hyperaemia 

 nothing is positively known. 



The gases of the transudations consist of carbon dioxide besides 

 small amounts of nitrogen and traces of oxygen. The tension of 

 the carbon dioxide is greater in the transudations than in the blood 

 (EwALD). On mixing with pus the amount of carbon dioxide is 

 decreased. 



The extractives are, as above stated, the same as in the blood- 

 plasma; but sometimes extractive bodies occur, such as allantoin 

 in dropsical fluids (MOSCATELLI), which have not been detected in 

 the blood. Urea seems to occur in very variable amounts. Glucose, 

 or at least a substance which reduces copper oxide in alkaline 

 liquids, occurs in most transudations. Succinic acid has been 

 found in a few cases in hydrocele fluids, while in other cases it is 

 entirely absent. Leucin and tyrosin have been found in transuda- 

 tions from diseased livers and in pus-like transudations which have 

 decomposed. Among other extractives found in transudations we 

 must mention uric acid, allantoin, xanthin, creatin, inosit, and 

 pyrocatechin. 



As above stated, irrespective of the varying number of form- 

 elements contained in, the different transudations, the quantity of 

 albumin is the most characteristic chemical distinction in their 



