ACTION AND USES OF SALICYLIC ACID, ETC. 469 



quickened by the stimulation of the peripheral vagi and 

 respiratory centres produced by sodium salicylate and sali* 

 cylic acid; but after large doses the respiratory centres are 

 depressed and paralyzed and death takes place by asphyxia. 



Temperature. — Medicinal doses do not influence the 

 normal temperature of healthy animals, but do often lower 

 bodily heat in fever, and frequently induce sweating. The 

 largest therapeutic doses must be given to secure an antipy- 

 retic action. The physiological details concerned in the 

 reduction of febrile temperature have not been ascertained. 



Kidneys and Elimination. — Salicylic acid, salicin and 

 sodium salicylate circulate in the blood as sodium salicylate 

 and are eliminated in the urine as salicyluric and salicylic 

 acids. This happens in this wise : Some of the salicylic 

 acid of sodium salicylate combines with glycocoll in the 

 body and forms salicyluric acid. HC.H5O3 -f- C2H5NO2 (gly- 

 cocoll) = HCgHgNO^ (salicyluric acid) + HoO ; while some of 

 the sodium salt is decomposed by phosphoric acid in an acid 

 urine into salicylic acid. Like quinine, the excretion of sali- 

 cylic acid begins soon and goes on slowly. Therefore large 

 doses given continuously may accumulate in the body. The 

 quantity of urea and uric acid in the urine is increased very 

 considerably by salicylic acid, but the urine itself may either 

 be increased or diminished in amount. It is made aseptic 

 by the escaping salicylic acid, or in the case of salol, by 

 both carbolic and salicylic acids. The urine of animals 

 taking salicylic acid may be rendered green by indican and 

 pyrocatechin, formed through the action of pancreatic juice, 

 and takes on a purple color with ferric chloride. 



Toxicology. — In man, continued large doses give rise to 

 delirium, vomiting, depression of the circulation, epistaxis, 

 hsematuria, and retinal haemorrhages. The herbivora are not 

 easily affected by large doses of salicylic acid, or salicylates, 

 but dogs exhibit nausea and vomiting, accelerated respira- 

 tion, irregular pulse, loss of muscular strength, staggering 

 gait, stupor, and, if death occurs, it is preceded by slow 

 breathing, dilated pupils, dyspnoea, and convulsions due to 





c>u.iFonja^ 



