224 
NATURE 
| Fuly 14, 1870 
of producing a Lead of fructification of the Zeniel/ium type. Thus, 
in fact, there appeared to be a strong tendency in the /e/tothrix 
filaments and in the loose spores found within the crystal, to deve- 
lope into the same kind of organism when either of these was 
placed under the influence of other and more suitable conditions. 
In the crystal itself, apparently, just as the conditions were 
not suitable for the germination of the spores, so they were not 
favourable for the developmental conversion of the confervoid- 
looking filaments into a fungus. 
Whether there was any genetic relationship existing between 
these confervoid-looking filaments which commenced life as Zef/o- 
thrix threads, and the few scattered spores which were frequently 
found with them within the crystal, is not quite certain. If 
any relationship did exist, however, it could only have been of 
one kind : the spores mzy have been descendants from the matter 
of the filaments, but the filaments were most certainly not deve- 
lopments from the spores. The spores existed singly or in groups 
of twos and threes. They were never seen in organic connection 
with the filaments, so that I am inclined to believe they were not 
even formed by a process of budding. They must, then, either 
have derived their origin from a minute speck of the matter of 
the filament which subsequently grew into a spore,* or they must 
have been evolved de xevo where they were found. just as we are 
compelled to imagine that the similar spores must have been 
evolved de novo within the flask used in Axferiment 19, at first 
by a coalescence and re-arrangement of colloidal molecules, 
and subsequently by a process of development similar to what is 
represented in Fig. 19, And, if the fungus-spore and the con- 
fervoid-looking filament both tend towards the same ultimate 
developmental form, we can only attribute this to the fact of the 
existence of a harmony between the ‘‘ conditions ” and such an 
organism. The conlervoid filament and the fungus-spore are 
both produced within the same crystal: they seem to be but 
different products of what appears to us to be the same matter 
and the same ‘‘ conditions,” and if minute differences may have 
existed at first tending to make the initial modes of development 
different, the main intrinsic similarity manifests itself at last by 
leading them both along a line of development which terminates 
in a common organic form. 
For these various concurrent reasons, therefore, I deem it 
much more probable that the filaments and spores found within 
the crystals of tartrate of ammonia have been developed from 
specks of Living matter there evolved de ove, rather than that 
they have originated from germs of similar pre-existing organisms 
which had accidentally been enclosed within the crystals. 
Before closing this paper, it will be necessary that I should 
refer more particularly to a certain part of M. Pasteur’s re- 
searches, seeing that these have so strongly influenced the opinions 
of very many scientific men on the question of the truth or falsity 
of the doctrines of the heterogenists. As an experimental 
chemist, M. Pasteur takes a most honourable position in the 
foremost rank of workers, and all his investigations on this 
subject appear to have been conducted with the most scrupulous 
care. His reasonings, also, may seem at first sight to be all con- 
vincing, so that most people might be inclined to admit that he 
had ‘‘mathématiquement demontré,” as he so frequently claims 
to have done, all that he had set himself to prove. The case 
may s.em at first a poor one indeed for the heterogenists ; but as 
soon as one gets over the first impressions produced by the 
various experiments, and begins to inquire whether the reason- 
ings concerning them have been in all cases fair and logical, 
then it may be seen that the evidence against the occurrence of 
heterogenesis is very far from being so strong as it, at first sight, 
appeared. 
On two or three occasions, when it was very important that 
results should be looked at from different points of view, M. 
Pasteur has altogether failed to do this, and has wished to 
interpret them only in accordance with the views of the pansper- 
matists, gzzelly ignoring the equally legitimate interpretation of 
the same results which might have been gwen by the hetero- 
genists. At present I shall confine myself to one instance of this 
kind, because I think that on this particular point the reasonings 
of M. Pasteur are as mischievous as they are illogical. If others 
_ * A mode of origin of spores which is, I believe, quite familiar to fungolo- 
gists, 
+ This form of fungus-spore seems to be most prone to occur where differ- 
ent ammoniacal salts are employed. It has been met with not only in the 
tartrate of ammonia solutions, but also in those containing oxalate of am- 
monia and carbonate of ammonia respectively. And it has been found in no 
other of my experimental fluids. 
were to follow his example, then certainly we could never hope 
to get rid of the clouds of controversy which at present obscure 
this subject. 
The experiments of Schwann were for some time erroneously 
believed by very many to have upset the doctrines of the hete- 
rogenists. No erganisms, it was said, were ever developed in 
hermetically sealed vessels when the solutions containing the 
organic matter had been boiled, and when all the air which was 
allowed access to them had been previously calcined. Schwann’s 
experiments did yield uniformly negative results when solutions 
of meat were employed; though his experiments concerning 
alcoholic fermentation yielded results which were sometimes 
positive and sometimes negative. M. Pasteur also, for a time, 
obtained only negative results in repeating the experiments cf 
Schwann. In these experiments, however, he had generally 
made use of ‘‘l’eau de levire sucrée,” of urine, or of some 
other fluid which was naturally unfitted to undergo evolu- 
tional changes of a high order, or even to produce lower 
organisms in great abundance.* But there came a time 
when M. Pasteur chanced to repeat his experiments, using pre- 
cisely the same precautions as before, and yet the results were 
quite different—organisms were now found in his solutions. 
There was one important difference, it is true. In these latter 
experiments, M. Pasteur had made use of milk. Now the quantity 
of organic matter contained in milk is, of course, very great ; 
it is a highly nutritive and complex fluid. It might, therefore, 
and ought, perhaps, to have suggested itself to M. Pasteur that 
the different results of his later experiments were possibly expli- 
cable on the supposition that the restrictive conditions—the 
boiling of the solution and the closed vessel already containing 
air—were too potent to be overcome by the organic matter in the 
one solution, whilst they were not too potent and could not 
prevent evolutional changes taking place in that of the other. 
For if, in accordance withthe belief of the evolutionists, different 
organic fluids have different initial tendencies to undergo the 
changes of evolution, it may be easily understood that as the 
conditions favourable to evolution are more and more restricted, 
certain of these fluids may altogether cease to undergo such 
changes, others may manifest them to a meagre extent, and others 
still, only a little more fully. Therefore, if under the conditions 
peculiar to Schwann’s experiments, certain fluids with low eyo- 
lutional tendencies have given rise to no organisms, there is 
nothing whatever contradictory in the fact if it is subsequently 
ascertained that other fluids, with greater inherent capacities ot 
undergoing change, will, notwithstanding all the restrictive 
conditions, pass through certain Life-producing changes. When 
subjected to a pressure of one atmosphere, water boils at 212° F., 
alcohol at 173° F., and ether at 96° F. The restrictive condition, 
or atmospheric pressure, is here in each case the same, only, 
having to do with differently constituted fluids, it is natural 
enough to look for different results under the influence of like 
incident forces. Ether raised to a temperature of 100° F. would 
rapidly disappear in the form of vapour, though no such result 
would follow the heating of water to a similar extent. And 
similarly, whilst milk might be capable of yielding organisms in 
Schwann’s apparatus, another fluid less rich in organic matter 
might fail to do so, It seems almest incredible that such consi- 
derations should not have suggested themselves to M. Pasteur ; 
but yet we have no evidence that they did occur to him.t On 
* In order to avoid circumlocution in this note, I speak from the evolu- 
tionist’s point of view. And whether the organisms found in a given fluid 
have been actually produced therein, or have only there undergone develop- 
ment, we may, for the sake of argument, measure the evolutional capacity 
of a fluid by the amountand kinds of organisms which are produced ina given 
quantity of it, ina definite time, and at a given temperature. We must not, 
however, judge of the evolutional qualities of a fluid by its mere tendency to 
emit a bad odour in ashort space of time. A certain fluid—urine for instance 
—judged by these qualities, may be disagreeably putrescible, though 
its evolutional tendencies may be quite Jow. By many experimenters this 
difference has not been appreciated, and they seem to imagine that in 
employing urine they make use of a fluid which is very favourable for such 
experiments. But they forget that urine is an effete product containing com- 
paratively stable compounds, which have already done their work in the 
body. It may after a short time swarm with bacteria, and these may be 
followed by fungi; but there is no comparison between the actual quantities 
even of these organisms, which will be developed in equal amounts of milk 
and urine respectively, when they are both exposed to the air for the same 
time in similarly-shaped vessels, and under the same bell-jar. The milk soon 
becomes actually solid with fungus growths. M. Pasteur’s ‘‘l'eau de leviire 
sucrée,” by his own confession (oc. cz#, note, p. 58) is never found to contain 
any of the higher ciliated infusoria, and in all probability, though it 
produces fungi, these are met with in much smaller quantity than they would 
have been in an equal bulk of milk under the same conditions. 
+ The experiments and reasonings to which I am now alluding are 
co in pp. 58—66 of M. Pasteur’s Memoir (An. de Chim. et de Phys, 
1862), 
