THE TAR ACIDS. 
181 
§ 226.] 
the minimum lethal dose for man at 15 grms. (231*5 grains), which 
would be about *2 per kilo., basing his estimate on the following reason¬ 
ing. In 33 cases he had a fairly exact record of the amount of acid 
taken, and out of the 33 he selects only those cases which are of use 
for the decision of the question. Among adults, in 5 cases the dose 
was 30 grins., and all the 5 cases terminated by death, in times vary¬ 
ing from five minutes to an hour and a half. By other 5 adults a dose 
of 15 grms. was taken ; of the 5, 3 men and a woman died, in times 
varying from forty-five minutes to thirty hours, while 1 woman re¬ 
covered. Doses of 11*5, 10*8, and 9 grms. were taken by different men, 
and recovered from ; on the other hand, a suicide who took one and 
a half teaspoonful (about 6 grms.) of the concentrated acid died in fifty 
minutes. Doses of *3 to 3 grms. have caused symptoms of poisoning, 
but the patients recovered ; while higher doses than 15 grms. in 12 cases, 
with only one exception, caused death. Hence, it may be considered 
tolerably well established that 15 grms. (231*5 grains) may be taken 
as representing the minimum lethal dose. 
The largest dose from which a person appears to have recovered is 
probably that given in a case recorded by Davidson, in which 150 grms. 
of crude carbolic acid had been taken. It must, however, be remembered 
that, as this was the impure acid, only half of it would be really carbolic 
acid. The German Pharmacopoeia prescribes as a maximum dose *05 
grm. (*8 grain) of the crystallised acid, and a daily maximum quantity, 
given in divided doses, of *15 grm. (2*3 grains). 
§ 226. Effects on Animals. —Carbolic acid is poisonous to both 
animal and vegetable life. 
Infusoria. —One part of the acid in 10,000 parts of water rapidly 
kills ciliated animalcules—the movements become sluggish, the sarcode 
substance darker, and the cilia in a little time cease moving. 
Fish. —One part of the acid in 7000 of water kills dace, minnows, 
roach, and gold-fish. In this amount of dilution the effect is not ap¬ 
parent immediately ; but, at the end of a few hours, the movements 
of the fish become sluggish, they frequently rise to the surface to breathe, 
and at the end of twenty-four hours are found dead. Quantities of car¬ 
bolic acid, such as 1 part in 100,000 of water, appear to affect the health 
of fish, and render them more liable to be attacked by the fungus growth 
which is so destructive to fish-life in certain years. 
Frogs. —If -01 to *02 grm. of carbolic acid be dissolved in a litre 
of water in which a frog is placed, there are almost immediately signs 
of uneasiness in the animal, showing that pain from local contact is 
experienced ; a sleepy condition follows, with exaltation of reflex 
sensibility ; convulsions succeed, generally, though not always; 
then reflex sensibility is diminished, ultimately vanishes, and death 
occurs ; the muscles and nerves still respond to the electric current, 
