Apr. 13, 191S 



Disinfection of Hides 



71 



Table III. — Germicidal efficiency of mercuric chlorid and formic acid by the rod method, 

 without addition of organic matter 



EXPERIMENT s" 



« Incubated 5 days. 

 t> Not exposed. 



Hydrogen-sulphid solution used for neutralization of mercury. 



Experiment 6, on the other hand, indicates that with an addition of 

 defibrinated blood mercuric chlorid, i to 4,000, plus i per cent of formic 

 acid, is not able to kill spores of the A. M. S. strain in 24 hours (Table IV). 



Table IV. — Germicidal efficiency of mercuric chlorid, with or without formic acid, by the 

 rod method, with and without addition of organic matter 



EXPERIMENT 6 « 



Rod 

 No. 



Disinfectant (lo c. c.) and dilution. 



Q^^Jitity j^.^^ j,j 



Result. 



Mercuric chlorid (i:4,ooo)+fonnic acid ( i per cent) . 

 Mercuric chlorid (i:4,ooo)H-fonnic3cid (i per cent). 

 Mercuric chlorid (i:5,ooo)+formic acid (i per cent) . 

 Mercuric chlorid (i:s,ooo)+formicacid (i per cent). 



Mercuric chlorid (i: 1,000) 



Mercuric chlorid (1:1,000) 



Control rod 



C. c. 

 None. 



None. 



Hours. 



24 



C) 



No growth. 

 Growth. 

 No growth. 

 Growth. 

 No growth. 

 Growth. 

 Do. 



o Incubated 3 days. Saturated aqueous solution of hydrogen sidphid used for neutralization of disin- 

 fectant. 



* Not exposed. 



In another experiment with various dilutions (Table V, experiment 7) 

 there were 9 c. c. of disinfectant plus i c. c. of defibrinated blood in 

 each tube. 



Experiment 7 was repeated with the result given in Table V, experi- 

 ment 8. 



In experiment 9 the technique was the same as for experiment 8, the age 

 of the culture being approximately the same (Table V, experiment 9). 



Table V. — Germicidal efficiency of mercuric chlorid, with and without formic acid, by 

 the rod method,'^ with addition of defibrinated blood 



EXPERIMENT 7 * 



Rod 



No. 



Disinfectant (lo c. c.) and dilution. 



Mercuric chlorid (i:2,ooo)+formic acid (i per cent). 

 Mercuric chlorid (i:3,ooo)+formic acid (i per cent). 

 Mercuric chlorid (i:4,ooo)+formic acid (i per cent). 



Mercuric chlorid (i:i,ooo) 



Control rod 



Time of 

 exposure. 



(«) 



Result. 



No growth. 

 Growth. 



Do. 



Do. 



Do. 



" Hydrogen-sulphid solution used to neutraUze disinfectant. ... rjc- ..it^i,^ 



b The quantity of disinfectant used in experunents -, 8, and 9 included i c. c. of defibrmated blood. 

 c Not exposed. 



79827°— 15 6 



