354 
Action of Anesthetics 
t Monthly Microscopical 
Journal, June 1, 1869. 
pendent living animal, wMch througli repeated fissions gives origin 
to an infinite number of ordinary reptant Amoehse ; while the freely- 
motile parent, pursuing its course, may from time to time, in tlie 
same manner, plant in congenial localities other such founders of 
populous colonies. 
Such speculations as these, vain and futile as they must neces- 
sarily be, in the absence of direct observation to support them, may 
yet serve to direct attention, and to point out the road for further 
investigations ; and whatever may be the results which attend them, 
one incontestable fact remains in our possession — that our pools 
and ditches afi'ord more than one species of free-swimming Amoebm. 
Yl.~Action of Anaesthetics on the Blood Corpuscles, By J. H. 
McQuiLLEN, M.D., D.D.S., Professor of Physiology in Phila- 
delphia Dental College. 
In the October number of the ' Dental Cosmos ' a report was 
presented of a series of experiments performed by me, on a number 
of animals, with the view of ascertaining whether the assertion 
made by a distinguished experimentalist and scientist of England, 
that nitrous oxide, even under the most delicate manipulation, 
would prove destructive to life, could be possible. These experi- 
ments, which clearly demonstrated the assertion to be unfounded, 
were not performed in private, but in the presence of a number of 
gentlemen whose experience in the use of anaesthetics, and whose 
scientific knowledge made them competent judges. First per- 
formed before the members of the Odontographic Society of Penn- 
sylvania, they were repeated, after an interval of three weeks, on 
the same animals, in the presence of the members of the Biological 
and Microscopical Department of the Academy of Natural Sciences. 
A month subsequent to the last-named occasion one of these 
animals, a rabbit, in the presence of a number of gentlemen, was 
placed under the influence of nitrous oxide, and kept in a profound 
state of narcosis for one hour and five minutes, by alternating 
atmospheric air and nitrous oxide, removing the inhaler ever and 
anon for that purpose. Without question the animal could have 
been kept in the same condition double or treble the time without 
injury to it, for in a few minutes after removing the anaesthetic 
entirely the animal was restored to consciousness, and leaped from 
the table to the floor, and for a number of weeks after this ran 
about my premises in a healthy and lively condition, and no doubt 
would have been still alive had I not demonstrated on him before 
