40 
On account of its germicidal efficiency and deodorant action formalin 
^ould seem to be one of the most useful agents for the disinfection of 
infected human discharges when used in a 10 per cent dilution, allow- 
ing an exposure of one hour after thorough mixing. 
disixft:ctiox of spftum. 
In order to determine the efficiency of formalin for the destruction of 
tubercle bacilli in sputum the following experiment was done: 
Ten cubic centimeters of sputa from an advanced case of pulmo- 
nary tuberculosis was added to ISO cubic centimeters of sterile water, 
and the mass of sputum broken up as much as possible. An amount 
of the mixture of sputum and water equal to that used to inoculate 
the guinea pigs after exposure to formalin was given to a guinea pig 
as a control. Sufficient formalin was added to the sputum to make a 
5 per cent solution by volume. At intervals of fifteen minutes up to 
one hour a small amount was given to a guinea pig intraperitoneally. 
with the following result: 
Table Xo. 34. 
Time. 
Death in — 
Post-mortem findings. 
1-5 minutes 
. . . 71 davs 
Generalized tuberculosis. 
30 minutes 
. . . 31 davs 
Do. 
lominme? 
. -. 72 davs 
Do. 
60 minutes 
. . . Killed 5 months later . . 
. Xo indication of tuberculosis: had gained in weight. 
The control pig died in thirty-five days with lesion of generalized 
tuberculosis. 
The ex})eriment was repeated with another specimen of sputum with 
practically the same result. 
It would seem from the above that 5 per cent formalin in one hour 
was sufficient to render tuberculous sputum harmless to a gtiinea pig. 
ACTION OF FORMALIN ON TETANUS ANT) DIPHTHERIA TOXINES. 
Aronson (19) called attention to the fact that formalin, in the pro- 
portion of 1 to oiMj. added to diphtheria toxine. was sufficient to protect 
a guinea pig against 100 fatal doses of the toxine. 
Burckhard (50) found that formalin, when added to tetanus toxine 
in the proportion of 1 to 250. was sufficient to protect a mouse against 
a dose of tetanus toxine that caused the death of the control in twenty- 
four hours. Burckhard does not seem to have determined the least 
fatal dose of his tetanus toxine. 
Aeither of them states how long the formalin was left in contact 
with the toxine before it was injected into the animal. My work on 
the action of formalin was all tested on guinea pigs, and the MLD of 
toxines accurately determined. 
