XxX. 
ACTION OF SALTS. 
WHILE some of the metallic salts, and especially those of mer- 
cury, silver, and gold, have remarkable germicidal power, others, 
even in concentrated solutions, do not destroy the vitality of bacteria 
exposed to their action. For convenience of reference we shall con- 
sider the agents in this group in alphabetical order, but first we give 
Miquel’s tables of antiseptic value. This author recognizes the im- 
portance of experiments to determine the restraining power of chem- 
ical agents for various species of pathogenic bacteria, but says : ‘‘ As 
to me, faithful to a plan I adopted at the outset, I will treat the sub- 
ject ina more general manner by making known simply the mini- 
mum weight of the substances capable of preventing the evolution of 
any bacteria or germs. The method adopted is very simple. Toa 
liquid always comparable to itself it is sufficient at first to add a 
known weight of the antiseptic and some atmospheric germs or adult 
bacteria, and to vary the quantity of the antiseptic until the amount 
is ascertained which will preserve indefinitely the liquid from putre- 
faction. In order to obtain germs of all kinds in a dry state it suf- 
fices to take them, where they are most abundant, in the dust col- 
lected in the interior of houses or of hospitals; and to procure a 
variety of adult bacteria we may take the water of sewers.” 
SUBSTANCES EMINENTLY ANTISEPTIC, 
Efficient in the 
proportion of— 
Mercuric iodide, 1: 40000 
Silver iodide, 1: 33000 
Hydrogen peroxide, . 1: 20000 
Mercurie chloride, 1: 14300 
Silver nitrate, 1: 12500 
SUBSTANCES VERY STRONGLY ANTISEPTIC. 
Osmic acid, 1: 6666 
Chromic acid, 1: 5000 
Chlorine, 1: 4000 
Todine, : 1: 4000 
Chloride of gold, . 1: 4000 
Bichloride of platinum, 1: 3333 
Hydrocyanic acid, 1: 2500 
