le) eae 
are subme1 
for five minutes. 
NATURE 
505 
above 100 C. by increasing the pressure under 
which ebullition is effected, beyond the normal atmospheric limit. 
A fourth point to which we gave attention was the possible 
_ preservative effect of ‘‘ lumps” on Bacteria or their germs. No 
one would have supposed that Dr. Bastian neglected the precau- 
tion of removing large particles of cheese from his experimental 
infusion. We always strained our cheese emulsion very care- 
fully, or else filtered it. Prof. Cohn found that an infusion made 
by boiling a pea in water developed Bacteria when the pea was 
left in it ; but if the pea were removed, and the infusion subse- 
quently reboiled, no Bacteria weredeveloped. We found that lumps 
of cheese could really act as protective hiding-places for Bacte- 
rian contamination. In a retort—similar in every respect to 
Dr. Bastian’s—this result was first obtained, though other re- 
torts similarly treated were barren. Accordingly we prepared 
twelve tubes exactly alike, with the exception that in six the 
cheese was added as an emulsion, in the other six in the form of 
lumps. The tubes were closed, and submerged in boiling water 
Of the ‘‘emulsion ”-tubes, one burst in the 
boiling, the other five were barren ; of the ** lumpy ”-tubes, four 
developed Bacteria in quantity, two remained barren. 
==!n the experiments recorded in NATURE, vol. viii. p. 141, by Dr. 
Sanderson, it is shown that even when “‘lumps” are avoided, 
and the infusion heated by submergence in boiling water, this 
may not prevent the development of Bacteria when a large bulk of 
material is employed. But boiling for sucha length of time as one 
hour, or heating to ror” C., always gave him a barren infusion. 
Dr. Sanderson does not believe that there is a definite relation 
between the precise temperature to which the infusion is exposed 
and the destruction of Bacterian contamination, but that the 
Jonger heating, or the heating to a Aigher degree, will increase 
the chance that Bacteria or their germs are destroyed. Further, 
Dr. Sanderson’s results agree with those of Dr. Pode and myself 
as to simple turnip infusion. With this infusion I understand 
that he has not found the same length or amount of heating 
necessary as with the turnip infusion to which a fragment of 
cheese has been added. 
And now, I wish very briefly to point out where Dr. Bastian’s 
statements are affected by these results. It is necessary that this 
should be clearly and simply put, because I find that many persons 
are under the impression that the investigation of the grounds of 
Dr. Bastian’s statements has shown that there was some solid 
foundation for them. ‘This is, however, in my opinion, not the 
case. It is zo¢ ‘‘ beyond all question of doubt or cavil that liv- 
ing Bacteria, Torula, and other low forms of life will make their 
appearance and multiply within hermetically-sealed flasks (con- 
taining organic infusions) which had been previously heated to 
212° F, even for one or two hours.” On the contrary, no organic 
nor inorganic infusion has been contrived by Dr. Bastian nor by 
anyone else which will develop Bacteria, still less Torulze, after 
exposure for one hour (or even less) to 212° F. ‘This is the con- 
clusion given by the impartial examination of the subject, indi- 
cated in the experiments above quoted. 
Moreover, the statement in the second quotation from Dr. 
Bastian is abundantly contradicted by the experience of Dr. 
Sanderson, Dr. Pode, and myself. Such a turnip-infusion, 
placed as directed by Dr. Bastian, does zo/ invariably become 
turbid in one or two days, owing to the presence of myriads of 
Bacteria. We have often kept such infusions free from Bacteria 
for manydays, and I preserved one in a retort with its beak in- 
clined downwards for more than six months, clear as crystal, but 
amply capable of sustaining the life of Bacteria, as was proved 
by its accidental contamination a week ago. 
It is my opinion that the only fositive addition to knowledge 
which this inquiry abou: the development of Bacteria in infu- 
sions has led to is, that when you have cheese-emulsion, or similar 
material present in an infusion, you must be a little more careful 
about heating it than when you have not, if you wish to destroy by 
the agency ot heat the life of Bacteria or their germs contained in 
the infusion. How it is that cheese-emulsion helps the Bacterian 
contamination to escape destruction we do not know. Possibly 
in the same way as the larger lumps do. But that matter 
remains for inquiry when more is ascertained as to the natural 
history of the Bacteria. I think we may now feel fully satis- 
fied that ‘‘archebiosis” or “abiogenesis” is not in any way 
rendered more probable than it was before by Dr. Bastian’s 
experiments with organicinfusions. Prof. Smithand Mr. Archer, 
of Dublin—eminent authorities in the study of the lower algaee— 
have criticised in detail and suggested explanations of some of 
the statements in the third part of ‘* The Beginnings of Life,” 
viz., statements relating to the transformation of various species 
of organisms into others, They show (the reader may consult 
Prof. Smith’s paper in the October number of the Quarterly 
Journal of Microscopical Science, 1873) that the asserted ‘‘ facts” 
of transmutations are ot facts. It is abundantly demonstrated 
that the fundamental observations recorded by Dr. Bastian are 
erroneous, and that he has been mistaken. 
Exeter College, Oxford, Sept, 26 E. Ray LANKESTER 
Variations of Organs 
My father finds that in his letter, published in your number 
for September 25, he did not give with sufficient clearness his 
hypothetical explanation of how useless organs might diminish, 
and ultimately disappear. I therefore now send you, with his 
approval, the following further explanation of his meaning. 
If one were to draw a vertical line on a wall, and were to 
measure the heights of several thousand men of the same race 
against this line,recording the height of each by driving in a pin, 
the pins would be densely clustered about a certain height, and 
the density of their distribution would diminish above and below. 
Quetelet experimentally verified that the density of the pins at 
any distance above the centre of the cluster was equal to that at 
a like distance below ; he also found that the law of diminution 
of density on receding from the cluster was given by a certain 
mathematical expression, to which, however, I need here make 
no further reference. A similar law obtains, with reference to 
the circumference of the chest ; and one-may assume, with some 
confidence, that under normal conditions, the variation of any 
organ in the same species may be symmetrically grouped about 
a centre of greatest density, as above explained. 
In what follows I shall, for the sake of brevity, speak of the 
horns of cattle, but it will be understood that my father con- 
siders a like argument as applicable to the variations of any 
organs of any species in size, weight, colour, capacity for 
performing a function, &c. 
Supposing then that a race of cattle becomes exposed to un- 
favourable conditions, my father’s hypothesis is that, whilst the 
larger proportion of the cattle have their horns developed in the 
same degree as though they had enjoyed favourable conditions, 
the remainder have their horns somewhat stunted. Now, if we 
had made a record of the length of horn in the same species under 
favourable conditions, we should, as in the case of the heights of 
men, have a central cluster, with a symmetrical distribution of 
the pins above and below the cluster. According to the hypo- 
thesis, the effect of the poor conditions may be represented by 
the removal of a certain proportion of the pins, taken at hazard, 
to places lower down, whilst the rest remain i sfat# guo. By 
this process the central cluster will be slightly displaced down- 
wards, since its upper edge will be made slightly less dense, 
whilst its lower edge will become denser; and further, the 
density of distribution will diminish more rapidly above than 
below the new central cluster. 
Now, if horns are useful organs, the cattle with shorter horns 
will be partially weeded out by natural selection, and will leave 
fewer offspring ; and after many generations of the new con- 
ditions, the symmetry of distribution of the pins will be restored 
by the weeding out of some of those below the cluster, the cen- 
tral cluster itself remaining undisturbed. 
If, on the other hand, horns are useless organs, the cattle with 
stunted horns have as good a chance of leaving offspring (who will 
inherit their peculiarity) as their long-horned brothers. Thus, 
after many generations under the poor conditions, with continual 
intercrossing of all the members, the symmetry of distribution 
will be again restored, but it will have come about through the 
general removal of a// the pins downwards, and this will of 
course have shifted the central cluster, 
If, then, the poor conditions produce a continuous tendency to 
a stunting of the nature above described, there will be two ope- 
rations going on side by side—the one ever destroying the sym- 
metry of distribution, and the other ever restoring it through the 
shifting of the cluster downwards. 
Thus, supposing the hypothesis to be supported by facts (and 
my father intends to put this to the test of experiment next 
summer), there is a tendency for useless organs to diminish and 
finally disappear, besides those arising from disuse and the 
economy of nutrition. 
Down, Beckenham, Oct. 4 , Grorce H. DARWIN 
