GLANDULAR SECRETIONS. 



93 



larger proportions in the urine of the lower vertebrata than in mamma- 

 lia, in whom there exists only about one part in a thousand of urine. 

 It is crystalizable, tasteless, inodorous, and nearly insoluble in water. 

 It exists in healthy urine in combination with a base, either am- 

 monia or soda, which latter, according to Liebig, is derived from 

 the bibasic phosphate of soda, which by yielding up a part of its 

 base gives the acid reaction to the urine that characterizes its healthy 

 state. Its affinity for the base, however, is so feeble, that it is readily 

 thrown down by any other acid in the urine. According to Keller, 

 uric acid is not replaced by Hippuric in the urine on the adminis- 

 tration of Benzoic acid. The amount of uric acid is not dependent 

 on waste or diet ; but often on disease, as gout, in which it is often 

 deposited from the blood, in combination with soda, around the 

 affected joints, forming chalky concretions. The urates are com- 

 monly red. The presence of lactic acid as a constituent of healthy 

 urine is denied by Liebig. 



The urine contains also various saline matters, such as muriates, 

 sulphates, and phosphates ; the latter supposed to be derived from 

 the waste of the nervous tissue, into whose composition phosphorus 

 enters. The phosphates are commonly yellowish white in colour. 

 The quantity of salts in the urine is never 

 the same in the same individual in like 

 spaces of time ; the urine of men, however, 

 generally contains a relatively larger por- 

 tion of salts than that of women. 



The total suspension of the urinary se- 

 cretion is attended with rapidly fatal re- 

 sults, the patient dying with symptoms re- 

 sembling those of narcotic poisoning. 



Besides the essential constituents already 

 mentioned, the urine often contains acci- 

 dentally mixed substances, such as articles 

 of food, of drink, or of medicine, which 

 pass into it unchanged or changed, and 

 can sometimes be detected in it in an in- 

 conceivably short time after administration. 



The spermatic secretio7i is formed by the 

 testes, another tubular gland consisting of 

 lobules formed of convoluted seminiferous 

 tubes. The number of lobules is about 450 

 in each testis, and that of tubules about 840. 

 The different parts may be seen in Fig. 24. 



Fig. 24.* 



The diameter of the 



tubes is generally very uniform ; they anastomose freely with each 



* A view of the minute structure of the testis; 1, 1, tunica albuginea ; 2, 2, corpus high- 

 morianum ; 3, 3, tubuli seminiferi convoluted into lobules; 4, vasa rocta ; 5, reto testis ; 6, 

 vasa efFerentia ; 7, coni vasculosi constituting the globus major of the epididymis ; 8, body 

 of the epididymis ; 9, its globus minor ; 10, vas deferens ; 1, vasculum aberrans or blind duct. 



