94 JVetw Anaesthetic Agent. 
or twenty thin courses, each separated by a layer of shale, some^ 
times of equal thickness to the limestone, though generally thiner. 
The shale separating the lower courses is green like that below, 
but higher it becomes of the same color and character as that 
above. The interlaminated shale is in all cases destitue of fossils. 
The shale is partially exposed in several small streams, and in 
the lower escarpment which extends westward from Rochester. 
In the town of Sweden, that escarpment has become higher, and 
the shale is in some places well exhibited. One of the best lo- 
calities is at Marshall's saw-mill, in the town before mentioned, 
where the small stream (a branch of Salmon creek) has excava- 
ted its channel in this rock. The banks scarcely differ in color 
and appearance from the soil around, and it is only from fossils 
that the mass is distinguished from ordinary clay. At one point 
where there has been a fresh exposure, the rock appears in all its 
character, and contains abundance of fossils. — Jfat. Hist. JV. Y. 
NEW ANESTHETIC AGENT. 
BY J. Y. SIMPSON, M. D., OF EDINBURGH. 
Our object now, however, is not so much to direct attention to 
the administration of ether as to record the fact of another chemi- 
cal body having been discovered which exerts the same influence 
upon the system, but is much more readily administered and free 
from some of the disagreeable consequences that now and then 
attend the taking of ether. This substance is called chloroform, 
or perchloride of Formyle; and curiously enough, has little re- 
semblance to ether in its composition. Ether is composed of 
oxygen, carbon, and hydrogen; whilst chloroform has no oxygen, 
and in addition to carbon and hydrogen contains chlorine. This 
substance was originally discovered by Souberain and Leibig: 
but the properties of its vapor were first ascertained a few weeks 
ago by Professor Simpson of Edinburgh. In order to produce 
insensibility by this agent — which, like ether, is a fluid, but less 
volatile — it is not necessary to use complicated apparatus. Sim- 
ply sprinkling it on a handkerchief and sponge and applying it 
to the nostrils during inspiration is sufficient. The effect on the 
nervous system is produced more rapidly than by ether; and the 
sleep or insensibility occasioned by the new agent is of a more 
profound kind than that caused by the old one. The quantity of 
the chloroform required is much less than of ether; amounting in 
most cases to at least nine-tenths less. Its smell is much less 
disagreeable. We have made enquiries, and find that at several 
hospitals in London this new remedy has been tried, and that it 
