338 THE SECRETIONS: 



One of the most important of Wohler^s discoveries is, that 

 the neutral vegetable salts become modified in their passage 

 through the system, and are found in the urine as carbonates. 

 A few hours after the use of these salts, the urine becomes 

 alkaline, is frequently turbid from the deposition of phosphates, 

 and effervesces briskly on the addition of an acid. 1 If the dose 

 is very large, oxalate of lime may frequently be detected. 

 Similar results follow from the use of alkaline lactates ; Lehmann 

 found, that two hours after taking two drachms of lactate of 

 soda, alkaline urine was excreted. That this change is effected 

 after the salt has entered the blood, and not in the intestinal 

 canal, is proved by an experiment performed by Mr. J. Goodsir, 

 at my request. A drachm of acetate of potash was dissolved 

 in an ounce and a half of water, and injected into the femoral 

 vein of a dog, whose urine had been previously ascertained to 

 be acid. The urine passed about an hour after the operation 

 was alkaline. A similar experiment has been since made by 

 Lehmann, who injected a drachm of lactate of potash into the 

 jugular vein of a dog, and found the urine alkaline an hour 

 afterwards. The process is one of simple combustion : each 

 atom of acetic acid (of the acetate of soda) combines with eight 

 of oxygen, and yields four atoms of carbonic acid and three of 

 water, or C 4 H 3 O 3 + 8O = 4CO 2 + 3 HO, and each atom 

 of lactic acid combines of twelve of oxygen, forming six of 

 carbonic acid and four of water, or C 6 H 5 O 3 + 12 O = 6 CO a 

 + 5 HO. 



In a series of 268 experiments instituted by Millon and 

 Laveran, with the tartrate of potash and soda, (Sodse potassio- 

 tartras. Ph. L.) they found the urine more [or less alkaline in 

 175, acid in 87, and neutral in 6 cases. This apparent dis- 

 crepancy was doubtless dependent on the degree of concen- 

 tration of the saline solution. (See page 149.) 



We have already mentioned that benzoic and cinnamic acids 

 are converted in the organism into hippuric acid, and then ex- 

 creted by the kidneys. 



Vegetable bases. Quinine, when administered in large doses, 

 has been noticed in the urine by Piorry, Landerer, and others. 



1 Some excellent observations on the physiological action of these salts will be found 

 in Dr. Pereira's Treatise on Food and Diet, p. 29. 



