Fuly 17, 1873) 
diameter, which on introduction i .to urine reproduced the mov- 
ing Spiriilum, now of very Jarge size, and sometimes remarkably 
- branched, but as time passed grad:al'y growing a smuller and 
smaller progeny as the liquil became vitia‘ed, till at length it 
Jost in the urine its spiral shape, and yeturn+d to the appearance 
of the minute ordinary Bacterium fi-st seen in the milk. These 
_ may serve as samples of this c’ass of observations, which proved 
on the one hand how utte:ly fallacious are any descriptions 
hitherto given of Bacteria acc rding to form, size or movement, 
yet, on the other hand, showing tiat the different Bacteria, like 
the different Oidia, retained ami all their variations their distinct 
specific characters. 
The fermentative changes induced in the media by the intro- 
duction of the various organisms wer: next alluded to. The 
_ test-tubes of the experiment with unboiled milk were shown, and 
it was pointed out that each different organism was accompanied 
by a different appearance of the milk, implying that each was 
_ associated with a special chemical chanze in the fluid in which it 
grew. An enlarged sketch was also exhibited of the boiled milk 
_ glasses as they were seen some weeks after they had been inocu- 
; lated with the various Bacteria, showing that no two of those 
glasses were alike. In that containing the Bacteria derived from 
: a drop of tap-water introduced into urine the milk had changed 
_ to a beautiful green colour ; that with the kind which formed the 
Spirillum in urine was a pure white curdy mass, sharply acid to 
_ test-paper, while a third, inoculated with a curious irregular form 
__ of Bacterium from another of the milk-flasks, was of umber brown 
colour. This glass was brouzht to the meeting because it was of 
_ especial interest, not only on account of its peculiar tint, but be- 
i ‘cause it was an instance of a primary alkaline fermentation of 
milk. Another miik glass had been inoculated with the same 
organism, and had undergone the same change, as:uming in a 
few days the same umber brown colour, accompanied by power- 
ful alkaline reaction. This particular Bacterium was in some 
_ forms undistinguishable from pairs of granules of a form of 
**Granuligera,” which occurred in one of the milk glasses asso- 
_ ciated with the large Bacteria above mentioned ; but the Granu- 
ligera having been obtained unmixed by introducing it succes- 
sively into liquids which permitted its growth, but not that of 
the Bacterium, it proved to be a feeble acid ferment of milk, not 
producing any effect upon its col mr. One of the glasses sketched 
~ was of peculiar interest, because it contained a large motionless 
Bacteritn, which had been the sole product of exposure of a 
glass of tlie boiled milk for an hour in a sitting room, the fungus 
spores that in all probability entered with it having been pre- 
vented from developing by the growth of the Bacterium. 
It happened that the Bacterium thus derived from the 
air refused to grow in Pasteur’s solution, urine, or turnip 
infusion, so that if the experiment had bein performed 
with either of those fluids, it would have afforded negative re- 
sults as regards the Bacterium, though fungi would probably 
have appeared ; and this might have been quoted as a good-illus- 
tration of absence of Bacteric development after atmospheric 
exposure. 
The Oidium, which, as before mentioned, was a powerful pu- 
trefactive ferment of urine, produced scarcely any effect on milk, 
which had remained unchanged in flavour for seyea weeks, al- 
though converted into a thick mass, not by coagulation of the 
casein, but simply by the dense jungle of the fungus filaments, 
_ while test paper indicated merely a very faint increase of alkaline 
reaction, The fluid remaining thus unimpaired in quality, ex- 
ct the luxuriant growth and healthy appearance of the 
ungus in it, contrasting strikingly with its characters in urine, in 
which it rapidly occasioned putrcfaction, and thea formed merely 
a scum of torulvid rounded cells. 
In describing these facts, the author did not affect the circum- 
locution that would be necessary in order to avoid using the lan- 
guage of the germ theory, As stated at the outset, his original 
object in the investigation had not been to prove that theory, but 
to throw light upon the nature and habits of the fermenting 
organisms. Nevertheless, fer the sake of any who might still 
entertain doubt upon the question, it might be well to point out 
that the facts which had been adduced were irreconcilable with 
any other view. It was plain that they utterly disproved the 
oxygen theory, while they indicated with sufficient distinctness 
that all instances of so-called spontaneous generation had 
been due simply to imperfect experimentation. It re- 
mained to consider shortly the only other rival theory, 
the somewhat specious one of chemical ferments. After 
pointing out some of the inconsistencies of that theory 
NATURE 233 
with the facts observed, and how its difficulties became in- 
creased with the discovery of every new organism with its 
corresponding chemicil change, requiring the a-sumption of a 
new anl purely hypothetical ch-mical ferment, the author 
reminded the Society that in trath thers was not a fact in 
chemis'ry to favour the belicf that any sv stmce destitute of 
vita‘ity possessed the one faculty which dis inguished all true 
fermentation, viz the property of self-pro xazatio 1 of the fe ment. 
Perhaps the most remarkable instance of a che nicil ferment was 
the res lution of the amygdalin of the bitter almond into the 
essential oil of bitter almonds, hydrocyanic acid, formic acd 
and glucose under the influence ofemu'sin. The amygialin nei her 
gained nor lost a single atom, but was simply broken up into - 
new compounds under the iofluence of the peculiar albuminous 
principle emulsin. ut did the emulsin undergo multiplication 
as in the true fermentations? On the contrary, it had been 
shown by Liebig and Wohler in their original paper * that a 
certain weight of emulsin would only break up a limited 
quantity of amygdalin, and that the emulsin when afterwards 
separa‘ed no longer affected amygdalin. So far from having the 
property of self-propagation, it lost its catalytic power in the act 
of catalysis. Thus the chemical ferment theory was in truth 
utterly destitute of scientific basis as explaining trae fermentation. 
Such being the case it was contended that the germ theory 
must now be regarded as demonstrated ; viz. that putrefaction 
and other true fermentations characterised by indefinite multipli- 
cation of the ferment are ciused by the growth of living 
organisms, which, whil2 capable of great variations according 
to the circumstances in which they are plazed, retain their 
specific characters like larger plants, and like them spring only 
from pre-existing similar organisms. 
Nevertheless the so-called chemical ferments had a high 
degree of interest in this ques’ion, as very likely playing an im- 
portant part in bringing about the chemical changes, For just 
as it was proved that a peculiar albuminous principle, emulsin, 
existing in the sweet as well as in the bitter almond, but absent 
from the pei, or bean, or other leguminous plants examined by 
Liebig and Wohle, could break up as much as ten times i s weight 
of a stabte crystallisable substance like amygdalin, so it seemed 
probable that other peculiar albuminous principles might exist 
in other plants, such as the fungi, and in like manner break up 
larger or smaller quantities of other stable organic compounds. 
In this sense, then, as intervening between the growth of the 
organisms and the resulting decompositions, the theory cf 
chemical ferments might be welcomed as a valuable hypothesis. 
Lastly, the author showed some blood obtained from a horse 
between three and four weeks previously, in the hope that by 
exposing the carotid artery autiseptically, and receiving the 
blood from it ino a ‘‘heated”’ vessel, and protecting it from 
dust, he might, after the clot had contracted, decant off the 
cleir serum, and inoculating or exposing the uncontaminated 
fluid, observe organisms and fermentations corresponding to 
those which occur in the practice of surgery. 
But to his great surprise day afrer day passed without the clot 
showing any sign of shrinking, and it remained still uncontracted. 
In the flask shown, the bufly coat was seen to be present onthe 
upper part of the still tremulous jelly-like coagulum, but instead 
of being powerfully pinched together into a comparatively small 
bulk bathed with serum, that part like the rest of the clat was 
everywhere in con act with the sides of the glass, and not a drop 
of serum was to be seen. At the same time there was no smell 
whatever about the cotton that covered the neck of the flask, 
showing that putrefaction had been ayoided, Somehow or other 
the exclusion of living organisms, while it had not interfered 
with coagulation, had prevented the fibrine from acquiring a 
tendency to shrink. ‘his fact, while entirely new, and openirg 
up a wide field of inquiry, was seen to tally with phenomena 
met with in surgical practice, such as the absence of shrinking of 
the plug of clot near a ligature placed upon an artery. It was 
an illustration of how little we are often able to predict what may 
arise when even the most familiar objects are placed in new 
circumstances, 
SCIENTIFIC SERIALS 
THE Yournal of Mental Science, July.—We have heard or 
read of a rather imoressionable gentleman who, as he perused 
Dr. Buchan’s ‘* Domestic Medicine,” fancied himself afflicted with, 
* See “ Annales de Chimie et de Physique,” 1837, p. 185. 
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