APRIL 8, 1897 | 
NATURE 
539) 
Texas fever in cattle, due to a protozoon parasite of the blood, 
is endemic, and practically harmless in the south; but when 
southern cattle are driven northward, and mixed with northern 
cattle, the latter contract:the disease in a form which is rapidly 
fatal. ao ; 
The above facts are selected out of many of a similar kind that 
are on record. It will be generally admitted that a race or 
species which has long been subjected to a zymotic disease 
acquires by selection a relatively high degree, if not of immunity, 
of endurance of the disease. 
It does not seem to have been sufficiently appreciated by 
naturalists that it may be beneficial to a species, in the struggle 
for existence, to refain the susceptibility to attack while develop- 
tng the power of endurance, instead of acquiring a total immunity 
from attack. 
When a species or race, thus subject to a mild form of a 
zymotic disease, meets the territory of a closely-allied species or 
race, it is evident from such cases as are cited above, that the 
disease, communicated to the newly-met race, may prove a most 
powerful agent for destruction, with the result of leaving a new 
territory open to the invaders. 
It has only lately been realised how susceptible insects are to 
various obscure diseases due to bacteria and fungi. In fact, in 
my studies of the Coccidz, I have come across numbers of 
parasitic fungi, which appear to be wholly undescribed and un- 
known. Therefore, when one insect supplants another in the 
mysterious way it sometimes does, it is easy to imagine the factor 
of communicable disease playing an important part. 
The purpose of this note is simply to draw attention to the 
matter, and to request those of your readers who may witness 
the supplanting of a native animal or insect by a foreign or in- 
vading one, to particularly note whether the former is attacked 
by any disease. T. D. A. COCKERELL. 
Mesilla, New Mexico, U.S.A., March 9. 
The Caucasus. 
Ir might be out of place to trouble your readers with any 
lengthy discussion of the many difficulties and snares that 
beset the path of the transcriber of Caucasian place-names, and 
of the discrepancies to which they may easily give rise. Nor 
shall I ask you for space to defend, in any detail against your re- 
viewer’s strictures, my own system—or want of system—in 
dealing with Caucasian nomenclature. In so far as I may have 
deviated from the principles laid down by the Committee of the 
Royal Geographical Society, of which I was a member, and 
adopted by the British Admiralty, the Government of the United 
States, and other bodies, I am very ready to submit myself to 
expert criticism or correction. 
In these notes, however, my object is not so much personal as 
general. It is to prevent the confusion of knowledge, and to a 
certain extent of tongues, which, I fear, must ensue should men 
of science in search of information about the Caucasus attempt 
to follow, without some further advice, ‘‘J. W. G.’s” summary 
suggestions. 
In the first place, I have to point out that your critic has 
failed to take into account a circumstance which is, in my opinion, 
of great importance, and to which, in my preface, I was at pains 
to call particular attention. The Caucasus, as we all know, is 
an annexed or conquered country. Consequently its place-names 
are not Russian, but, in the district with which I deal, for the 
most part Old Turkish or Georgian. Now scientific cartographers 
in this country are not, I believe, prepared, wherever and when- 
ever Russia may incorporate an Asiatic district, to substitute for 
the English forms of the native place-names transliterations from 
the forms they assume in Russian maps. Such a course has 
obyious disadvantages. It must obscure the meaning of many 
names, and give identical names different forms, according as 
they occur within or outside a political frontier. The question 
is a recurrent and a difficult one, not to be set aside lightly by 
an obtter dictum, or by an appeal to French usage. Under no 
‘circumstances, I must add, are British geographers likely to 
respond to your writer’s implied suggestion by assimilating their 
‘system to that in use in France. 
«J, W. G.” and Iagree, I am glad to find, in desiring to 
induce men of science in quest of accurate information as to the 
Caucasus, to seek it out from first-hand authorities. He recom- 
mends certain articles, printed in Russian, and published in 
NO. 1432, VOL. 55] 
Moscow and Tiflis periodicals by MM. Dinnik and Jukoff. 
I have good reason to believe that a knowledge of Russian is 
still far from universal, even among men of science. I shall 
therefore venture to suggest that our countrymen may gain some 
further assistance from the hundreds of pages devoted to the 
Caucasus, during the last ten years, in the Jowvzads of the Alpine 
Club and of the Royal Geographical Society. And I would add 
a few words of caution to beginners. M. Dinnik’s paper was 
written some years ago, when the New Survey was still far from 
complete, and his own travels did not suffice to fill in the gaps. 
On some matters, consequently, he may mislead—and has mis- 
led—his copyists. _M. Mikhailovsky’s tables of Caucasian 
Peaks, Passes, and Glaciers, issued in the Moscow Zem/euyed- 
yenze, should also be consulted. They are more up to date, and 
detailed, though he, too, fails in the personal knowledge of the 
localities essential to graphic and accurate description. More- 
over, his spelling of place-names frequently diverges from that 
of the preliminary sheets of the New Survey, privately com- 
municated to me by the Surveyors, which were my authority. 
It is with some surprise that I observe your critic’s statement 
that he has failed to find in my pages any reference to the 
writings of either M. Dinnik or my friend M. Jukoff. The 
former, I must confess, has slipped out of my index. But he is 
referred to in his proper place in the first chapter, and elsewhere. 
M. Jukoff is in my index, preface, first and many other chapters. 
I have mentioned both frequently in the Alpine and Geographical 
Journals, and I published a translation of a paper of M. Jukoff’s 
in the latter periodical. As to the map of M. Fournier’s, which 
** J. W. G.” cites, it is a geological map appended to a geological 
diploma essay printed at Marseilles lastautumn. Itcan hardly, 
I think, be cited as a geographzca/ authority. 
DovuGias W. FRESHFIELD. 
The Alpine Club, March 20. 
WE did not intend our remarks on nomenclature to be stric- 
tural, and we certainly offered no suggestions, summary or 
otherwise. We only pointed out some of the inconsistencies 
inevitable when place-names are not transliterated upon a definite 
system. The fact that the Caucasian place-names are derived 
from various languages had not been overlooked; but the rules 
laid down by the R. G. S. Committee, to which Mr. Freshfield 
refers, admit the principle in such cases of accepting the spelling 
of a standard national gazetteer or of official survey maps. Such 
a method may be philogically defective, but it is geographically 
convenient. Would Mr. Freshfield recommend a foreign 
geographer, writing about England, to abandon the recognised 
names in favour of the forms which may be used locally? To 
ignore the official spelling in many parts of the Russian Asiatic 
dominions would be to render the revision of place-names, to 
use Mr. Freshfield’s term, a ‘‘recurrent” difficulty, for the 
people are nomadic, and names come and go like fashions. There 
is probably no place for which a stronger case could be made out 
in favour of adopting the spelling of the official maps. We did 
not imply that the French method should be adopted in England ; 
what we said was that, owing to the variations adopted by Mr. 
Freshfield, sometimes avowedly for the sake of appearances, it 
was difficult to find his names in Fournier's map. We did not 
quote Fournier as a geographical authority. In regard to the 
two Russian authors to whom we referred, we remarked the 
absence of reference to their technical papers, instead of to those 
of general Western compilers, for information respecting the 
Caucasian glaciers. J. W. iG. 
The Laboratory Use of Acetylene Gas. 
Ir is evident from Mr. Munby’s letter, in your issue for March 
25, that he is unaware that atmospheric bumers adjusted for 
acetylene gas are, and have been for some time, articles of 
ordinary commerce. Up to the present time no satisfactory 
method has been found by which large and powerful Bunsen 
flames can be obtained free from smoking, as the mixture of 
acetylene gas with a small proportion of air is very explosive, 
and the Bunsen tubes used must not exceed 3-16 inch diameter. 
Any ordinary Bunsen adjusted for 20-candle coal gas, if not 
exceeding the bore stated, will be found fairly satisfactory with 
acetylene, the gas pressure being not less than 5 inches of water ; 
but the best results are obtained from burners rather different in 
proportions from the ordinary laboratory Bunsen. 
Warrington. Tiros. FLETCHER. 
