626 
NATURE 
[April 21, 1870 
Tyrolese Alps, and has even attempted to introduce into 
a small plot of ground in the mountains surrounding 
Innsbruck, a number of plants indigenous to the lowlands 
of the Tyrol, In this enterprise, however, he met with no 
very encouraging success; “the greater number of the 
plants which I brought to those heights with inexpressible 
toil, succumbed to the uncongenial Alpine climate ; and 
in the remaining small portion, I have noticed at present 
only very unimportant changes.” His conclusion from 
these experiments is “ that changed conditions of life can 
kill the species, or they can reduce it to a starved existence, 
but can in no case produce a divect change into a new 
permanent species adapted to its altered conditions.” 
Such change can only take place by the slow process of 
natural selection among slightly varying offspring from 
the parent species. The writer notices a number of 
interesting features that characterise the Alpine flora with 
which he is familiar, as contrasted with those found under 
other climatal conditions. One of these is the very small 
number of annual plants, which bear to perennials the 
proportion of 4 to 96, as contrasted with that of 42 to 58 
in the Mediterranean district, and of 56 to 44 in that of 
south-eastern Europe ; a result of the very short period 
of summer warmth, varying from 1} to 34 months, which 
does not allow time for the seeds to ripen. The same 
cause produces also the appearance in many Alpine species 
of the flower-buds at the close of the summer, ready to 
burst into blossom during the first days of returning warmth 
in the spring. The remarkably large proportion of Alpine 
plants with evergreen rosettes of fleshy or succulent 
leaves, Primulas, Gentianas, Androsaces, Saxifragas, 
Drabas, &c., he attributes to the advantages of some con- 
trivance for obviating the effects of the intense heat of 
the sun during the long days in their short summers, and 
also to the necessity that the plant should possess leaves 
at the very commencement of the warm season, in order 
to afford it a store of nourishment, and thus economise 
the whole of the brief period of vegetation. With this 
peculiarity he contrasts the poverty of the Alpine flora in 
plants possessing stores of w#derground nourishment in 
the form of bulbs, a class so abundant and prominent in 
the south of Europe. The necessity for great caution in 
deriving general conclusions from a small array of facts, is 
shown by the mention by M. Kerner, among the plants 
well adapted by their constitution to withstand the great 
alternations of an Alpine climate, of Dryas octopetala, a 
species which flourishes equally well in the remarkably 
uniform climate of the west coasts of Ireland and Scot- 
land. The want of any considerable number of large 
shrubs and forest trees is obviously due to the rigours of 
the climate ; and the almost entire absence of climbing 
and creeping plants indicates that protection from the sun 
is not one of the first conditions of existence, as it is in 
tropical forests. The large proportion of plants with 
flowers of intense hues, and the deficiency of spiny and 
stinging species, are not so easy to account for, though 
the author attributes the latter to the comparative absence 
of destructive animals ; and the former may possibly have 
some connection with the advantage derived from the 
speedy attraction of insects, after the flowers expand, to 
assist in their fertilisation. We can conceive no greater 
service to biological science than a series of observations 
on the floras of limited areas, both with respect to what 
they possess and to what they are deficient in, carried out 
with the care of those recorded in the work before us. 
A. W. B. 
The fourth volume of the A/ti della R. Accademia 
delle Scienze di Torino, contains several important papers 
on various departments of science. We may notice espe- 
cially Prof. Salvadori’s memoir on some birds from Costa 
Rica, and the same author’s monograph of the genus Cey2,; 
a memoir by M. F. Giordano, on the orography and geolo- 
gical constitution of the Gran Cervino ; and mineralogical 
papers by Prof. Struiver and Dr, Cossa, 
LETTERS TO THE EDITOR 
[Zhe Editor does not hold himself responsible for opinions expressed 
by his Correspondents. No notice is taken of anonymous 
communications. | 
Evidence concerning Heterogeny 
THE question of the truth or falsity of ‘‘heterogeny,” as it is 
called, is perpetually recurring both in your columns * and else- 
where, in connection with several of the most important scientific 
controversies of the day. It is a subject which has engaged my. 
attention for several years, and I am anxious to be permitted to 
lay before your readers as concisely as possible a statement of 
what appears to me to be its present position. 
I think the impression which most recent references to it 
are likely to leave on the minds of readers is this—viz., that 
while amongst the most advanced thinkers there is a gradually 
strengthening conviction that the weight of theoretical conside- 
rations is in favour of the actual existence of heterogeny as a 
real mode of origin of living beings, yet that the authority of M. 
Pasteur’s famous researches inclines the balance of experimental 
evidence heavily the other way. 
I am perfectly willing to admit the principle of authority in 
matters scientific as far as any reasonable person can admit it— 
that is to say, I believe it is natural and right that when a 
scientific man of so deservedly high reputation as M. Pasteur 
publishes a long series of carefully conducted researches, and 
announces the conclusions to which they lead him, and when no 
evident flaw can be shown in his processes, either of experimenta- 
tion or of reasoning, his conclusions should be accepted as 
against those of another comparatively unknown experimenter. 
But in the present case neither of these conditions is fulfilled. In 
the first place, instead of merely an unknown experimenter we 
have in this case a consensus of at least eight experimenters— 
some of them by no means unknown—who have given their best 
attention to the same investigation in different parts of the world 
and under widely differing conditions, and who agree in dis- 
puting M. Pasteur’s results.’+ 
In the next place, there is a step in M. Pasteur’s experimenta- 
tion which has been pointed out as a flaw, and of which it is in 
the power of any one of your readers to judge for himself by a 
process of simple inspection as to whether it really be a flaw or 
not. I refer to the subject of the microscopic power used by M. 
Pasteur in his investigation. The organisms which I found 
during my own experiments on this subject appeared often but 
little larger than a full point in the type used in your columns, even 
when seen with a power of 1700 diameters. In the woodcuts 
attached to my paper in the Proceedings of the Royal Society 
(April, 1865), they may be seen as they were kindly drawn for 
me by my friend Dr. Beale, who, though an uncompromising oppo- 
nent of the doctrine of heterogeny in all its forms, is a very high 
authority in microscopy; there can therefore be no question as to 
their size, nor as to their actual presence in the experimental 
vessels. Now under the power used by M. Pasteur (350 diam.) these 
organisms would be about =; part of the size which they appear 
in the drawings. Yet it is upon the authority of observations 
made with such a power that M. Pasteur has pronounced, not 
upon the fresence of these objects, but upon their adsence. It is 
now nearly five years since my obseryations were made public. 
Since that time several critics have noted them as requiring an 
answer, but, so far as I am aware, no answer has been made to 
them ; and meanwhile naturalists have gone on complacently 
quoting M. Pasteur’s experiments as having settled the question 
against heterogeny, even though they have not failed to acknow- 
ledge the weight of the theoretical considerations which tell in 
its favour. ; 
The theoretical aspect of the question I have fully discussed 
elsewhere, t and I will only here state my entire agreement with 
the belief expressed by Dr. Charlton Bastian in your issue of 
February 24, viz. ‘‘that the time is not far distant when the 
doctrine of the evolution of living things will be as much an 
* Narurg, Feb. 1, p. 351; Feb. 24, p. 424. 
+ x. Pouchet, ‘‘ Nouvelles ‘Experiences’ passim. 2. and 3. Joly and 
Musset, Comptes Rendus, 1860. 4. Schaafhausen, of Bonn, Cosffes 
Rendus, 1860 and 1862. 5. Mantegazza, of Pavia, see Cosyos, 1863, p. 630. 
6. Wyman, Harvard, U.S., American Fournal of Arts, &c., vol. Xxxiv., 
July 1862, vol. xliv., September 1867. 7. Proceedings of Royal Society 
G. W. Child, Oxford, June 1864 and April 1865. 8. Hughes Bennett, 
Edinburgh, Edinburgh Medical Fournal, March 1868, 
} ‘Essays on Physiological Subjects,” 2nd edition, pp. 137154. 
