14 
Anthrax spores . — Silk threads impregnated with anthrax spores not 
killed by thirty-five minutes exposure. Killed by nine days. 
Concludes that the disinfectant action is slow, but the antiseptic 
action more marked. 
Carlo Ascoli (32) used slips of bibulous paper impregnated with cul- 
tures of various micro-organisms. The disinfecting agent was allowed 
to act for difierent periods, washed in sterile water, planted in bouillon, 
and placed in the incubator for ten days’ observation. He found that 
5 per cent formalin killed V. cholerge in three minutes, anthrax bacilli 
in fifteen minutes, anthrax spores in five hours, B. diphtheri^e in ten 
minutes, and Staphylococcus pyogenes aureus in thirty minutes. 
Slater and Eideal (33) made experiments to determine the proportion 
of formaldehyde required to inhibit the growth of micro-organisms. 
Formalin was added to tubes of bouillon, so that they contained for- 
maldehyde in proportions vaiwing from 1: 1,000 to 1:20,000. These 
tubes were inoculated with various micro-organisms and placed in the 
incubator twenty-four hours. Vigorous cultures were used, either in 
bouillon or on agar. 
Organism. 
Proportion 
formalde- 
hyde inhib- 
iting 
growth. 
Proportion 
formalde- 
hyde allow- 
ing some 
growth. 
Remarks. 
Staphylococcus pyogenes 
aureus. 
B. typhosus 
B. coli communis 
B. anthracis 
Spirillum cholerae 
B. mallei 
1:5,000 
1:15,000 
1:7,000 
1:15,000 
1:20, 000 
1:20,000 
1: 7, 000 
1:20, 000 
1:20,000 
1: 20, 000 
1:10,000 
1: 20, 000 
1:10, 000 
1: 20, 000 
Growth poor, 1:10,000; delayed 
1:20,000. 
Very scanty. 
After 72 hours’ incubation. 
Scanty growth sixth day. 
On third day. 
B. pyocyaneus 
B. prodigiosiis 
B. lacticus 
B. butvneus Heuppe 
1:10,000 
miich, 
Billz threads infected hy soaking in twenty-four hour cultures; strength of formaldehyde 
being i per cent. 
Organism. 
Time required to kill microbes. 
Staphylococcus pyogenes aureus 
Between 50 and 60 minutes. 
Between 40 and 50 minutes. 
Between 30 and 40 minutes. 
Less than 15 minutes. 
Do. 
B. typhosus 
B. coli communis 
B. anthracis 
Spirillum choleree 
Silk threads infected tvith twenty-four hour cultures; strength of formaldehyde 1 : 1, 000. 
Organism. 
Was not killed 
after — 
Was killed in — 
B. anthracis (no spores) 
1 
30 minutes. 
2 hours. 
24 hours. 
Do. 
Do. 
12 hours. 
Spirillum cholerse 
Staphylococcus pyogenes aureus 
12 liours 
B. typhosus 
do 
B. coli communis 
do 
B. mallei 
11 hours 
Putrefactive organisms 
24 hours 
