292 OF THE SECRETIONS IN GENERAL. 



varies in all. This matter sometimes retains some of the pro- 

 perties of albumen, at other times, none 3 and hence an accu- 

 rate analysis, shewing the quantity and nature of this peculiar 

 matter, is above all to be desired. 



" If the several secretions be supposed to be deprived of their 

 peculiar matter and the remainders analysed, the same residue 

 would be found from them all, which also would be identical 

 with the fluid separated from the serum after its coagulation. 

 Thus we shoidd find, first, a portion soluble in alcohol, con- 

 sisting of the muriates of potash and soda, lactate of soda, and 

 of an extractive animal substance, precipitable by tannin ; and 

 secondly, of a portion soluble only in water, containing soda 

 (which acquires carbonic acid by evaporation, and is separable 

 by acetic acid and alcohol) and another animal substance, not 

 extract, precipitable from its solution in cold water, both by 

 tannin and muriate of mercury. Sometimes a vestige of phos- 

 phate of soda will also be detected. 



" The excretions are of a more compound nature. They all 

 contain a free acid, which is termed lactic, and in the urine this 

 is mixed with the uric acid. Urine seems to contain only a 

 single peculiar characteristic matter ; but milk has as many as 

 three, viz. butter, curd, and sugar of milk, which, however, seem 

 to be produced by different organs that mingle their fluids in the 

 same receptacle. The perspired fluid appears to have no peculiar 

 matter, but to be a very watery liquid, with hardly a vestige of 

 the albumen of the blood, and, in short, is the same as the 

 other excretory fluids would be when deprived of their peculiar 

 matter. If we suppose this matter taken away from those 

 excretions which possess it, the remaining fluid will be found 

 to have properties very different from the fluid part of the secre- 

 tions, when equally freed from their peculiar matter. That of 

 the excretions is acid, contains earthy phosphates, and when 

 evaporated, leaves a much larger residue than the fluid of the 

 secretions. This residue is yellowish-brown, of the consistence 

 o^f syrup, with an unpleasant sharp saline taste of the salts that it 



