WYMAN, ON THE FORMATION OF INFUSORIA, py 
presence was indicated, in the early stage of the experiments, 
by the formation of a film, which took place in some on the 
second, and in others not until the nineteenth day, and was 
afterwards proved by a careful examination with the micro- 
scope. Prof. Asa Gray witnessed the openings of some of 
these flasks, and satisfied himself of the presence of Infusoria 
in the contents. Vibrios, Bacteriums, and Spirillums wera 
the most frequently found, and in addition to these, as in 
expts. 10, 11, 12, 29, 31, 32, 33, either ferment cells, monads, 
or Kolpoda-like bodies were seen, some of them having ciliary 
movements. ‘Those forms which were observed the most fre- 
quently are among the lowest, if not the lowest of all known 
organisms. 
In many instances, a solution like that in the sealed flasks, 
and boiled for the same length of time, was exposed to the 
ordinary air of the room, in an open flask. Although the 
same forms were found in the two, they appeared much more 
rapidly in the open than in closed vessels, and the contents 
of the former soon became putrid, while those of the others, 
at the time of opening, were mostly not, and in a few in- 
stances only slightly so. 
We have, in addition, four experiments, viz., 34, 35, 36, 
37, made under increased pressure,and sealed by the third 
method; 34 and 386 were boiled five and ten minutes respect- 
ively, under two atmospheres, and 35 and 87, under five 
atmospheres for ten and fifteen minutes respectively. Evi- 
dence of life, consisting of Monada and Vibrios, was found 
in 84 and 85, but none in the others. 
The result of the experiments here described is, that the 
boiled solutions of organic matter made use of, exposed only to 
air which has passed through tubes heated to redness, or en- 
closed with air in hermetically sealed vessels, and exposed to 
boiling water, became the seat of infusorial life. 
The experiments which have been described, throw but 
little light on the immediate source from which the organisms 
in question have been derived. Those who reject the doctrine 
of spontaneous generation in any of the forms in which it 
has been brought forward, will ascribe them to spores con- 
tained either in the air enclosed in the flask, or in the 
materials of the solution. In support of this view it may be 
asserted, that it has been proved by the microscopical investi- 
gations of De Quatrefages, Robin, Pouchet, Pasteur and others, 
that the air contains various kinds of organic matter, con- 
sisting of minute fragments of dead animals and plants, also 
the spores of cryptogamous plants; and certain other forms, 
