Sune 30, 1870] 
NATURE 
yo 
other hand, there is the concurrent testimony of many observers 
to the fact that, after such exposure, germination would never 
take place, because the spores were no longer living. This was the 
result obtained in many experiments made by Builiard, and 
related in his ‘‘ Histoire des Champignons.” Mere contact with 
boiling water was found sufficient to prevent germination ; and 
_ H. Hoffmann* similarly ascertained that an exposure for from 
_ four to ten seconds to the influence of boiling water sufficed to 
prevent the germination of all the fungoid spores with which he 
_ experimented. The experience of other observers has been 
similar to that above quoted, and amongst these we may cite 
__M. Pasteur himself. Speaking of his experiments with boiled 
_ milk in Schwann’s apparatus, M Pasteur says :—‘‘ Jen’ai jamais 
yu seformer, dans le lait ainsi traité autre chose que des Vibrions 
et des Bacteriums, avcune Mucédiné, aucune Torulacke, aucun 
ferment végétal. I1n’y a pas de doute que cela tient a ce que 
_ les germes de ces derniéres productions ne peuvent resister a 
1oo° au sein de l’eau, ce que j’ai d’ailleurs constaté par des expé- 
riences directes.”"+ 
_ The evidence which we at present possess concerning the 
tenacity of life displayed by éacterta and widrios in fluids whose 
temperature has been raised, is just as decisive as that con- 
_ cerning the spores of fungi. M. Pouchet’s observations have lead 
him to believe that vibrios, in common with all the kinds of 
ciliated Infusoria, are killed by raising the temperature of the 
fluid which contains them to 55° C. M. Victor Meunier, also, 
_ never found any of these organisms alive after they had been 
similarly subjected to a temperature of 60° C. I have myself 
invariably found that vibrios were not only killed, but were 
broken up and more or less disintegrated, after the fluid had 
been boiled for even one minute. There is every reason also to 
believe that an exposure to similar conditions kills their less 
developed representatives—the primordial monads and bacteria. 
With reference to these organisms, however, one caution is 
5 necessary to be borne in mind by the experimenter. The move- 
_ ments of monads and bacteria may be and frequently are of two 
_ kinds. The one variety does not differ in the least from the mere 
molecular or Brownian movement, which may be witnessed in 
_ similarly minute non-living particles immersed in fluids ; whilst 
_ the other seems to be purely vital—dependent, that is, upon their 
_ properties as living things. These vital movements are altogether 
| 
J 
i Ne 
different from the mere dancing oscillations which non-living 
particles display, as may be seen when the monad or bacterium 
- darts about over comparatively large areas, so as frequently to 
_ disappear from the field of the microscope. After an infusion 
__has been exposed for a second or two to the boiling temperature, 
these vital movements no longer occur, though almost all the 
monads and bacteria may be seen to display the Brownian move- 
_ ment ina well-marked degree. They seem to be reduced by 
the shortest exposure to atemperature of 100°C., to the condition of 
_ mere non-living particles, and then they become subjected to the 
unimpaired influence of the physical conditions which occasion 
these molecular movements. 
Such is the evidence existing as to the power of resisting the 
destructive influence of heat, manifested by the organisms about 
which we are at present most interested. It is certainly harmo- 
nious enough with our ordinary experience, and is, therefore, 
not difficult for us to believe. Eggs of higher animals contain- 
- ing an embryo may fairly enough be compared with the lower 
organisms of which we have been speaking, so far as the matter 
_ of which they are composed is concerned; and knowing the 
profoundly modifying influence of water at a temperature of 
‘100° C. upon the comparatively undifferentiated matter of the em- 
_bryo and of the egg-—and also, we may add, even upon the differ- 
entiated tissues of the parent fowl—need we wonder much that 
the same temperature should have been found hitherto to be 
destructive to the simple and naked living matter entering 
into the composition of fungus-spores, and of bacteria and 
_ vibrios? If any other result had been ascertained, would there 
not have been much more reason for surprise ? 
We must therefore be very cautious how we attempt to set 
aside the conclusions which have been arrived at on this subject, 
based as they have been upon direct evidence of a most posi- 
tive character, on account of other evidence which is indirect 
and more or less ambiguous. Concerning the legitimacy of 
such an attempt which has been made by M. Pasteur, I shall 
_ have more to say hereafter. 
Passing on, then, to the more immediate consideration of our 
* Etudes mycologiques sur les fermentations. 
+ Annales de Chimie et de Physique, 1862, p, Go. 
subject, it should be distinctly understood that in all the discus- 
sions which have hitherto taken place on the possibility of the 
evolution of Living things, pre-existing orge7zz> matter has always 
been supposed to furnish the materials entering into the compo- 
sition of the new organisms. New combinations and re-arrange- 
ments have been supposed to take place amongst the molecules 
of this pre-existing organic matter, under the agency of some 
mysterious force or forces—which new combinations of pre- 
viously uncombined or differently combined molecules have 
been supposed to result in the production of such primordial 
living specks as monads and bacteria. The observations of 
preceding inquirers have also been conducted for the most part 
on infusions containing organic matter 7 solution; and since 
the molecules of such matter are then invisible, observers have, of 
course, been quite unable to follow, by any magnifying power at 
present attainable, variations in the modes of collocation of such 
invisible molecules. The minutest specks of living matter— 
the germs of monads and bacteria, and of the spores of 
fungi, less than sy4y,” in diameter—may be seen gradually 
appearing under the microscope in previously homogeneous 
solutions containing none of them.* But although micro- 
scopical investigation enables us to adduce evidence of just 
the same kind in elucidation of the mode of origin of cer- 
tain low organisms, as we possess in explanation of the mode 
of origin of crystals, + this evidence is not deemed adequate in the 
case of organisms. A living thing has been supposed to bea 
something altogether different, incapable of arising out of a mere 
collocation of matter and of motion ; and, therefore, under the in- 
fluence of this theoretical assumption, whilst chemists and physi- 
cists have thought that they could in a measure account for the 
genesis of crystals by reference to the affinities and atomic 
polarities of the ultimate constituents of such crystals, they have, 
for the most part, declined to adopt a similar mode of reasoning 
in order to account for the appearance of the minutest living 
specks in solutions containing organic matter. The-same reser- 
vation is likewise made by the major part of the biologists of the 
present day. Whilst it is not an article of faith—whilst such a 
surmise scarcely crosses our minds—that crystals always proceed 
from pre-existing germs, in the case of Living things, on the con- 
trary, the doctrine omne vivum ex vivo has become almost one 
of the, ‘forms of thought.” Principally owing, therefore, to 
certain theoretical views concerning Life, and in order to ac- 
count for facts which would otherwise be adverse to these, biolo- 
gists and others have been accustomed to make the most extensive 
postulations concerning the supposed universal distribution of 
“*germs” of all the lower kinds of living things ; whilst they 
have recourse to no parallel hypothesis to account for the appear- 
ance of crystals, although we know no more—can drive our 
knowledge back no further into the phenomena attendant upon 
the birth of crystals than we can into the phenomena which usher 
in the appearance of organisms. In each case, under suitable 
conditions, they appear at first as minutest visible specks, in 
solutions which were previously homogeneous. In the one 
* A more complete account of this part of the subject will be given ina 
work on The Beginnings of Life, shortly to be published. 
t Or, betterstill, concerning the mode of origin of those modified crystals which 
appear on mixing solutions of gum and carbonate of potash, as described by 
Mr. Rainey (Ox the Mode of Formation of the Shelis of Animals, &c., 
1858). The malate of lime contained in the gum is decomposed, but owing 
to the slow mixing of the solutions in the presence of gum, the insoluble 
carbonate of lime does not appear in its usual crystalline condition, but in 
globular modifications, resembling calculi. When portions of the two solu- 
tions are mixed under the microscope, Mr, Rainey thus describes what takes 
place :—‘‘ The appearance which is first visible is a faint nebulosity at the 
line of union of the two solutions, showing that the particles of carbonate of 
lime, when they first come into existence, are too minute to admit of being 
distinguished individually by the highest powers of the microscope. In a 
few hours exquisitely minute spherules, too small to allow of accurate 
measurement, can be seen in the nebulous part, a portion of which has dis- 
appeared, and is replaced by these spherical particles. Examined at a 
later period, dumb-bell-like bodies will have made their appearance, an l 
with them elliptical particles of different degrees of excentric.ty”’ (p. g). Mr. 
Rainey made use of one of Ross's }” object glasses. These modified 
crystals are produced with no more rapidity than the lowest living things 
seem to be in other solutions, during hot weather; and the shapes of the 
products in the two cases are remarkably similar, judging from Mr. Rainey’s 
figures. The protraction of the process, brought about by the presence of 
gum, serves to bring out more clearly the real relationship existing between 
the formation of crystals and that of the lowest organisms, in homogeneous 
solutions. 
That there are very strong reasons accounting for this belief I do not 
attempt to deny. There is, however, much evidence to show that the very 
same organisms which do propagate their kind after this acknowledged metho |. 
may themselves originate de nove. Whilst allowing, therefore, the widest 
generality to any given rule, we may well hesitate before, on this account, 
we reject certain other alleged facts which are complementary rather than 
contradictory. 
