580 
matter (owing to differences in chemical composition) 
these seeming contradictions may have no real sig- 
nificance; though the opposite point of view that my 
positive results may be due to the pre-existence of 
organisms in these particular solutions and not in the 
others which yielded negative results is a position that 
would seem quite impossible of reconcilement with 
the variations in composition above cited—even if the 
process of sterilisation had not intervened. 
Sterilisation and After-Treatment of the Experimental 
Vessels. 
The experimental tubes were prepared in this 
manner. A little more than half an ounce of either 
of the solutions was put into each of a number of 
sterilised glass tubes. These were then hermetically 
sealed, and subsequently heated for five to twenty 
minutes to temperatures ranging from 125° to 145° C., 
or else to 100° C. for twenty minutes on three suc- 
cessive days. 
As in all previous experiments concerning the pos- 
sibility of spontaneous generation by Pasteur, Pouchet, 
Tyndall, and many others, the destructive influence of 
heat was relied upon for ridding the fluids and vessels 
of any pre-existing living things that might be con- 
tained therein—these being very much less numerous 
in my saline solutions than in hay infusions and other 
organic media of which it was the custom formerly 
to make use. 
Saline solutions were used by me because they could 
be submitted, within limits, to higher temperatures 
than organic infusions without destroying any possible 
productivity ; and because in using them there would 
be a closer approximation to the conditions that must 
have existed when the surface of our earth first cooled 
down below the temperature of boiling water, so that 
a natural origin of living matter might thereafter 
become possible. 
After sterilisation the sealed experimental vessels 
are exposed to diffuse light and a varying amount of 
actual sunshine for periods of from four to ten months 
or more before the contents of the tubes are examined 
microscopically, though the terminal month may, with 
advantage, be passed in an incubator at some tem- 
perature between 27° and 37° C. 
When ‘controls’’ are opened, say any time within 
one or two weeks of sterilisation, no organisms, 
except it may be one or two embryonic forms, are 
to be found, especially if the solution of ammonic 
tartrate has been filtered through No. o Swedish 
paper, though when other tubes of the same series 
come to be examined after the several months of 
exposure to light and heat above mentioned many 
well-developed organisms are often found, which can 
be proved to be living. 
These organisms are for the most part Torulz, and 
minute simple moulds of different kinds. Specimens 
of such organisms are shown in Fig. 1, as they were 
taken direct from the tube, the Torule in this case 
being unusually abundant. 
Bacteria are much less frequently met with, mostly 
motionless, though occasionally motile. Plasmogenic 
products simulating cocci and bacilli in appearance 
are also by no means uncommon in these colloidal 
silicate solutions. 
According to De Barry and other authorities, no 
germs of moulds can survive a single immersion for 
a few minutes in water at 100° C.; while Torulz are 
uniformly admitted to be killed by immersion for a 
minute or two in water at 60° C. 
I have ascertained that the mixed Torule and 
fungus:germs to be found in the bloom on the surface 
of grapes have been killed by immersing the grapes 
for only thirty seconds in boiling water." 
4 See *' The ‘ Origin of Life,” 2nd edition, p. 96 (Watts and Co.) 
NO. 2308, VOL. 92] 
NATURE 
[January 22, 1914 
Further, | have found that the Torula and minute 
moulds that tend to appear after a short time in un- 
heated weak solutions of silieic acid are, like other 
fungus-germs, unable to survive a single boiling for 
five minutes. Yet the least severe sterilising heat - 
employed in my experiments has been a boiling for 
twenty minutes on three successive days. 
Objections and Replies Thereto, 
Those who rely upon existing evidence as to the 
thermal death-point of such organisms as have been — 
found within my tubes (rather than like Sir E. A. — 
Schifer pinning their faith to mere preconceptions 
as to the impossibility of the origin of living matter 
in these particular solutions) will agree that the 
sterilising processes employed by me should have been 
very much more than adequate to kill any germs of 
Torulaz or moulds that may have pre-existed within 
the tubes. 
Those who are ineredulous as to my results are 
compelled, therefore, to fall back upon one or other 
of the three following objections :-— 
(1) There are first the mere surmises of superficial 
objectors who postulate contaminated pipettes, or the 
dropping of organisms on to the microscope slide from 
the atmosphere before the application of the cover- 
glass. These are puerile objections against a pro- 
longed research such as mine. Of course, pipettes 
Fic. 1.—Large Group of 1 orula as taken direct trom tube. e 
No, 289. 520, 
have been carefully sterilised immediately before use ;_ 
and as for the dropping of organisms from the atmo- 
sphere, such objectors would find it hard enough, if 
they tried, to find definite kinds of organisms, and 
cften numbers of them (as in Fig. 1) on slides and 
under cover-glasses prepared by themselves. The 
next paragraph, however, will show the unreality of 
these mere surmises. ; 
(2) It is assumed by many that the bodies found by 
me in my tubes are not really organisms. It is 
thought that they must be mere plasmogenic simu- 
lacra of living things, such as Leduc, Herrera, the 
brothers Mary, and many others have found in silicate 
solutions. This objection has been made over and 
over again. It is true that such bodies are occasion- 
ally to be met with in my solutions, and however 
important these mere simulacra may be as _ inter- 
mediate products between living and non-living matter, 
the other bodies which I find are not of this order. 
Those who have seen some of my tubes opened, and 
the bodies in question taken therefrom, such as Profs. 
Hewlett and Shattock, Profs. Farmer and Blackman 
at the College of Science, and several others, ar 
unable to doubt that they have seen actual organisms 
taken from the tubes. 
Moreover, on August 18 I received a letter from 
Paris written by two celebrated plasmcgenists, Albert 
