468 



PRACTICAL PHYSIOLOGY. 



compared with those obtained by Salkowski's method showed the method 

 to be a fairly reliable one. Before adopting it as a standard method, 

 however, it will be necessary to study more fully the exact formula of 

 the mercury compound, as there can be no doubt that this is variable. 



The excretion of endogenous creatinin is increased after severe 

 muscular work. It is markedly diminished in amount in certain blood 

 diseases associated with enlargement of the spleen. Its excretion in 

 dogs after removal of the spleen is, however, not affected. It is said 

 also to be decreased in patients suffering from muscular atrophy, but I 

 have been unable to verify this. 



Ammonia. Estimation (Schlosing's Method). 25 c.c. of urine are 

 placed in a flat glass dish with vertical sides, and mixed with 20 c.c. 

 milk of lime. The vessel is placed on a ground glass slab, and is 

 covered by a glass triangle, resting on which is another vessel containing 

 20 c.c. of one-fifth normal or deci-normal sulphuric acid. The whole is 

 covered with a bell jar, and left standing several days. The lime expels 

 the free ammonia, which is at once taken up by the sulphuric acid. 

 The amount of acid which has not been neutralised, is then determined 

 by titration, as described on p. 244. 



a 



FIG. 274. Folin's apparatus for estimating ammonia. 



A much quicker and more accurate method for estimating ammonia 

 is Folin's. 



It depends on the fact that free ammonia is liberated from its salts 

 when a solution of the latter is made faintly alkaline, and, by bubbling 

 a fast current of air through such a mixture, the ammonia is carried 

 away and may be collected and measured by passing this air through 

 standard acid. 



