502 



Mr. Gr. S. Johnson. 



filtered to separate the flocculenfc amorphous mercury precipitate, and 

 the filtrate is received into a large glass vessel capable of holding about 

 60 litres. It is better not to operate with more than a litre of urine 

 at a time, because if a larger volume be taken there is risk of forma- 

 tion of spherical mercury salt before the filtration is complete, and of 

 its retention upon the filter. But the mercuric chloride acts so effec- 

 tually in preventing putrefaction that sample after sample may be 

 treated as above directed, and filtered into the same receptacle, in 

 which the spherical compound accumulates and awaits the convenience 

 of the operator. When a sufficient quantity has accumulated, it is 

 thrown upon a filter, washed with cold distilled water till the wash- 

 ings are only slightly troubled by silver nitrate, and the washed com- 

 pound is then dried over sulphuric acid in vacuo and weighed. 



The following tables will give an idea of the scale upon which I 

 have operated, and will also show how the weight of mercury salt 

 obtained is proportional to the amount of reduction exerted by the 

 specimens examined : — ■ 



Table I. 



No. of men 



<^r»n fvi nnf mor 



UUii vX 1 KJ Vx vXXlhl • 



Volume of 



Specific gravity 

 at 16° C 



Picric acid 

 reduction 



glucose. 



Reaction to 



ilLJU 1 life. 





c.c. 

 5,600 



1-021 



gr. per fluid oz. 

 0-6 



Feebly acid 



3 



1,600 



1023 



0-65 



Neutral 

 Feebly acid 



3 



900 



1-023 



0*87 



4 



1,200 



1-018 



075 



Feebly acid 



2 



1,100 



1-023 



0-75 



Acid 



2 



1,000 



1-027 



0-88 



Feebly acid 



2 



790 



1-025 



0-87 



Acid 



3 



1,100 



1-023 



0-87 



Acid 



3 



750 



1 -031 



1-00 



Acid 



1 



900 



1-031 



100 



Acid 



1 



1,000 



1-026 



0-85 



Acid 





2,000 



1-026 



0-85 



Acid 



1 



1,300 



1-027 



0-90 



Acid 





15,400 



1-017 



0-62 



Acid 



