198 
NATURE 
[Fuly 7, 1870 
Experiment 15.—A flask containing a solution of a potash- 
and-ammonia alum, and of tartar emetic, 77 vacuo, which had 
been hermetically sealed twenty-eight days previously, after the 
fluid had been boiled for fifteen minutes, was opened on March 
17, 1870. The fluid then had a decidedly acid reaction. * 
The solution continued clear throughout ; there was no trace 
of a pellicle and no deposit at the sides, though a whitish floc- 
culent mass was seen at the bottom of the flask after the first 
fortnight, which gradually increased in amount, and at last 
formed a mass about }” in diameter. 
On microscopical examination the white mass was found to 
be made up of aggregations of variously sized and irregularly 
shaped protein-looking particles which were imbedded (4)in a most 
distinct hyaline jelly-like material. The granules were highly 
refractive, altogether irregular in shape, and they varied in size 
from goa" Up to sy'57” indiameter. Though most of the particles 
Fic. 14.—Fungus met with in a solution containing Potash-and-Ammonia 
Alum, with Tartar Emetic. 
were motionless and imbedded in the jelly, very many were seen 
exhibiting active and independent movements ; some of these 
were in the form of little double spherules (¢), and a very few others 
resembled bacteria about sj,” in diameter, though they did 
not possess the accustomed joint. 
Three fungus-spores with thick double walls were seen. Each 
these was about y;\;;" in diameter. Within one of them 
here were only a number of granular particles (c), but within each 
of the other two there was a large and somewhat irregular 
nuclear mass. 
In addition there was found the complete fungus which is 
represented in the figure (a), with all its spores. In a portion of 
one of the granular aggregations, a mass of about thirty spores 
seemed to be undergoing evolution in a part of the mucoid 
material through which some fine granules were disseminated. 
Experiment 16.—A flask containing a solution of carbonate of 
ammonia and phospate of soda 7 vacuo, which hac been her- 
metically sealed thirty days previously after the fluid had been 
boiled for twenty minutes, was opened on March 1, 1870. The 
fluid was then found to have a very slightly alkaline reaction. 
The fluid had continued clear and no pellicle had formed on 
its surface, though a light granular deposit had slowly collected 
in small quantities on the bottom and sides of the flask. 
On microscopical examination, bright highly refractive moving 
particles, very similar in appearance to those of milk, were met 
with, of all sizes varying between pty,” and zy,” in diameter. 
There were also numerous crust-like aggregations of such par- 
ticles. Small Zorz/a cells, the smallest being about z¢4yy” in 
diameter, were very abundant. They were either single or 
double, and each ceil contained a distinct nuclear particle ; some 
of the larger ones, indeed, contained two. All these cells ex- 
hibited very slight oscillating movements. Two cellular look- 
ing bodies, each about 3,455” in diameter, and having granular 
contents, were also seen; and, in addition, there were two or 
three patches of a peculiar spirally twisted fibre-like organism, 
* This solution was prepared one evening when I had been busy in devising 
several other mixtures with which I deemed it desirable to experiment. At 
the time I thought I possessed a pure potash alum, and by some strange 
oversight I had failed to ‘recognise that, if this had been the case, I should 
have been employing a solution which contained no nitrogen. Having once 
planned what mixtures I would use, I did not further think of each of them 
analytically. It was not, therefore, till my attention was called by Dr. 
Sharpey to the assumed absence of nitrogen in the above solution, that I 
became aware of this. It seemed very incredible that an organism should 
have been produced ina solution containing no nitrogen. I then had some 
of my supposed potash alum carefully tested, and it was found to contain a 
considerable quantity of ammonia. I then also learned that as ammonia- 
alu is now the alum of commerce, it is very difficult to get a pure potash 
alum, 
growing in portions of the granular crust, and apparently repre- 
senting an embryonic condition of a spiral fibre, closely resem- 
Fic. 15.—Embryonic condition, and also more mature stage, of a Spiral- 
fibre Organism met with in a solution of Carbonate of Ammonia and 
Phosphate of Soda. 
bling those met within previous experiments. Neither of these 
gave the smallest trace of a colour reaction with the polariscope. 
B.—Lxperiments in which the fluids employed were raised to a 
temperature of from 146° to 153° C. for four hours, after all 
air had been exhausted and the flasks had been hermetically 
sealed, 
A temperature of 100° C. has been the degree of heat to which 
all the fluids in the experiments hitherto related haye been sub- 
jected. It has been previously found that none of the lower 
organisms so treated, and which had been afterwards examined, 
were able to survive an exposure for a few seconds to such 
a degree of heat. They had nearly all been destroyed, in 
fact, at a temperature many degrees short of this. Many 
different kinds of organisms have been submitted to this test, and 
without the occurrence of any exceptions* such a degree of heat 
has always proved fatal to them. Looking, therefore, on the 
one hand, at the uniformity in the experimental evidence, which 
has itself extended over a wide basis, and, on the other, at the 
comparative uniformity in fundamental nature and property exist- 
ing between all the lowest kinds of Living things, which are almost 
wholly made up of a more or less naked living matter or proto- 
plasm, it is only reasonable for us to conclude, until direct evi- 
dence can be adduced to the contrary, that that which holds 
good for the many without exception may prove to be a rule of 
universal application. Therefore it was that the Societé de 
Biologie (and M. Pasteur himself for a long time) assumed that 
none of the lower kind of organism could survive in a fluid which 
was raised to a temperature of 100° C. 
No evidence has as yet been adduced which is capable of 
shaking the validity of this conclusion, and the experiments just 
related are much stronger in favour of the view that the 
organisms found in my experimental fluids were there evolved de 
novo than were all the negative results in the experiments of 
Schwann (upon which so much stress was formerly laid) in 
proving the impossibibility of such a mode of evolution. And 
yet Schwann’s experiments were deemed by many so conclusive 
that they were thought to have upset the doctrine of hetero- 
geny. The fluids with which he experimented were only exposed 
to a temperature of 100° C., and, working under a particular set 
of conditions which are considered to be adverse to the occur- 
rence of evolutional changes, he found no organisms therein when 
his flasks were opened. I, on the contrary, subjecting my expe- 
rimental fluids to the same temperature, though exposing them 
subsequently to quite different conditions, which I suppose to be 
more favourable for the occurrence of evolutional changes, do 
find organisms in the fluids when the flasks are opened. Ilis 
negative results ay be only applicable to the particular fluids 
and the particular conditions under which he worked ; but my 
* No exceptions, that is, amongst such organisms as are met with in infu- 
sions. The only known exceptions to that rule being met with in the case of 
seeds naturally provided with a hard ¢es¢a, and after these had undergone an 
extreme amount of desiccation. 
