TRANSACTIONS OF THE SECTIONS. 
39 
but this effect is not permanent, but gradually disappears on expo¬ 
sure to the air. Its specific gravity (according to repeated trials 
made by two intelligent pupils of the author, Mr. Richard Austin 
and Mr. John Keogh, who assisted him in many of his experiments,) 
is about that of distilled water. It neutralizes the mineral and ve¬ 
getable acids, forming peculiar salts, some of which the author has 
obtained in a crystallized, and others in an imperfectly crystallized 
state. It undergoes no apparent change by being kept in close 
vessels for a considerable length of time. It is volatile below the 
point of boiling water. It precipitates the greater number of metals 
from their solutions, as those of silver, mercury, tin, antimony, man¬ 
ganese, of a white colour; iron of a green, cobalt of a pink, and 
gold and platina of a yellow colour. 
Salts of Nicotin .—A number of the salts ofnicotin, as the nitrate, 
sulphate, &c., crystallize in four- and six-sided prisms ; they are cha¬ 
racterized by having a sharp biting taste, analogous to that of aqueous 
nicotin : they are mostly soluble in water, and are easily decomposed 
by a slight increase of temperature. The nitrate is so susceptible 
of change, that it seems to undergo an incipient decomposition when 
exposed in solution for a few hours, and assumes a reddish colour. 
The author’s experiments have led him to conclude that nicotin is 
composed of carbon, hydrogen, oxygen, and nitrogen, but he is 
not yet satisfied as to its exact constitution. He made some ex¬ 
periments to try the effects of aqueous nicotin on small fishes, flies, 
moths, spiders, &c. A few drops of it diffused in a tumbler of wa¬ 
ter strongly acted on the nervous system of small fishes, imme¬ 
diately communicating to them an unusual but momentary energy, 
which was speedily followed by torpor. 
Butterflies, moths, spiders, were soon killed by being brought in 
contact with a weak solution of nicotin. Common flies resisted its 
action better than spiders, drones, bees, or wasps, and after immer¬ 
sion fora short time, again recovered on being exposed to the air for 
a few minutes. Common caterpillars of a large size, on being taken 
from cabbages, and instantly put into a weak solution of nicotin, ex¬ 
hibited some energy, but presently became insensible, and being 
considered as dead were suffered to remain in the solution for about 
half an hour ; they were then removed to fresh water, but exhibited 
not the slightest symptoms of life, but on being placed on a grass- 
plot near the house they all recovered, and were very active in the 
course of an hour. 
The author is of opinion that aqueous nicotin may admit of a 
number of useful applications, as in preparing specimens of natural 
history for the museum, in preventing the destructive effects of the 
insect tribes which infest plants and trees in gardens, conservatories, 
&c. And it seems highly probable that the salts of nicotin will ad¬ 
mit of useful medicinal applications. 
After the author had ascertained the principal facts already stated 
respecting nicotin, he found that he had been anticipated; he ob¬ 
served in the ‘ Quarterly Journal of Science, Literature, and Art,’, for 
