a 
v6 
June 23, 1923] 
NATURE 
at 
841 

Letters to the Editor. 
[The Editor does not hold himself responsible for 
opinions expressed by his correspondents. Neither 
can he undertake to return, nor to correspond with 
the writers of, rejected manuscripts intended for 
this or any other part of NATURE. No notice ts 
taken of anonymous communications.) 









































Dr. Kammerer’s Experiments. 
-_As I had the privilege of entertaining Dr. 
_ Kammerer in my house when he was passing through 
London, and of discussing his experiments with him, 
and as I acted as his interpreter when he replied to 
_ his critics at the meeting of the Linnean Society, 
Space may be permitted me in which to reply to the 
criticisms of Mr. Cunningham which appeared in 
Nature of May 26, and to those of Dr. Bateson in the 
_ issue of June 2. 
I will deal with Dr. Bateson’s remarks first. From 
his speech at the Linnean Society I gathered that Dr. 
Bateson completely withdrew his charges of bad 
faith on the part of Dr. Kammerer, and accepted his 
ublished results as genuine, claiming, however—as 
~ he had the full right to do—to differ from the deduc- 
tions which Dr. Kammerer drew from them. But 
_ Dr. Bateson’s letter reads like a prolonged imputation 
_ of fraud to Kammerer; he refers to Dr. Kammerer’s 
illustrations as like “spirit photographs,’’ and demands 
further evidence before he will base any conclusions 
on Dr. Kammerer’s work. Now, Dr. Kammerer 
_ explained at the meeting that the specimens shown 
_ by him constituted the salvage of the utter wreck of 
|_ the experimental laboratories at Vienna owing to the 
War. His work has been going on since 1900—the 
year in which, unless I am mistaken, Dr. Bateson 
b Bissgan his Mendelian work—and, in my opinion, the 
work has yielded results which are of as much 
importance in the study of heredity, from the evolu- 
tionary point of view, as all the Mendelian experi- 
ments together. 
The main point in Dr. Bateson’s letter is, however, 
that the specimen of Alytes shown by Dr. Kammerer 
to the Linnean Society did not show a typical 
“nuptial pad ”’ (Brunstschwiele), and that the alleged 
was in the wrong place, because it was only the 
: k of the hand which came in contact with the 
_ body of the female, so that the rugosities should be 
| there and not on the palm; further, that a typical 
nuptial pad showed papille, and that he could not 
° see them in the specimen. In proof of his assertion 
| that the normal contact between male and female 
_ takes place with the dorsal surface of the male hand, 
Dr. Bateson publishes bo el from a photograph of 
a pair of Rana agilis killed in the nuptial embrace. 
I ought to add that he was kind enough to send me 
oy a positive of this photograph, which shows 
_ his point more clearly than the print in Nature. 
E Let us deal first with the structure of the horny 
“patch. Dr. Bateson omits to say that at the meeting 
a section through one of these patches was shown 
under the microscope, and that, when the point of 
_ structure was raised in the discussion, Dr. Kammerer 
thought it too frivolous to reply to; he merely 
referred to the section which he had exhibited as 
answer. Dr. Kammerer, who has cut sections of the 
nuptial pads of all our common Anura, and can 
detect the species by the appearances shown by the 
‘microscopic preparation, assumed a similar know- 
ledge on the part of his audience—but, to judge 
from Dr. Bateson’s letter, he was rash in doing so. 
“I have, however, taken the trouble to refer to 
ataste’s original figures of the callosities (‘‘ Mémoire 
NO. 2799, VOL. 111] 
sur les brosses copulatrices des batrachiens anoures,”’ 
Annales des Sciences naturelles, 6me series, vol. 3, 
1876), and I have no hesitation in saying that 
the section shown in the Linnean Society displays 
almost exactly the same appearances as those figured 
by Lataste in the figure of a section through the 
nuptial pad of the closely allied genus Pelodytes. 
Further, I have had sections through the nuptial pad 
of Rana temporaria prepared in my laboratory, and I 
can see in them the same structures as were shown 
in Dr. Kammerer’s slide; of course, in Rana, as 
Lataste’s figures show, the papillae are very strongly 
developed—much more so than in Pelodytes or 
Alytes—but the essential structure is the same. The 
pad in Rana, to the naked eye, looks like a simple 
patch of pigment, and passing my finger over it I 
could not detect the papille by feeling. 
As to the position of the pad, Dr. Bateson seems 
to think that he has settled this question for all Anura 
by his photograph. Now Alytes belongs to the small 
family of the Discoglosside, probably the most 
primitive family of the Anura. This family includes, 
besides Alytes, the genera Discoglossus, Bombinator, 
Pelodytes, and Pelobates. Boulenger, in his mono- 
ae “The Tail-less Batrachians of Europe ”’ (Ray 
iety, 1897), gives details of the position of the 
Ss: 
(1) Pelodytes, on the inner side of the two inner 
fingers—the antibrachium, the brachium. 
(2) Discoglossus, on the inner and upper side of the 
three inner fingers. 
(3) Bombinator, on the inner side of the three inner 
fingers and the antibrachium. 
(4) Pelobates, copulatory excrescences absent. 
The fact is that the primary contact between male 
and female takes place neither with the dorsal nor 
the ventral surface of the hand, but with the radial 
edge, and this is in accordance with Dr. Kammerer’s 
experience ; for in Alytes the pad first appears here, 
as shown in Dr. Kammerer’s figures? (those criticised 
by Dr. Bateson in Nature of July 3, 1919), and only 
later extends to the other fingers. In tight embrace, 
as indeed Dr. Bateson’s photograph shows, the hand 
of the male becomes embedded in a fold of the 
female’s body, and it is then a question of the direction 
in which pressure is exerted whether the additional 
callosities will appear on the inner or on the upper 
sides of the fingers. Perhaps I may add that the 
specimen shown in the Linnean Society had been 
previously exhibited at Cambridge, where it was 
inspected by Dr. Gadow, probably the best herpeto- 
logist at present living in Britain. 
r. Gadow raised none of Dr. Bateson’s objections, 
but he added the extremely interesting information 
that in the Portuguese species, Alytes cisternasii, old 
males occasionally develop callosities on the tips of 
the two inner fingers. 
Dr. Bateson refers to Dr. Kammerer’s reply “ as 
disquieting to his disciples,” since Dr. Kammerer 
stated that he did not regard the nuptial pad as an 
adaptation. I fear that my translation of the reply 
must have been singularly defective if Dr. Bateson 
drew any such conclusion. Dr. Kammerer’s reply 
was that while, of course, the pad in Alytes was the 
revival of an ancestral nuptial pad, he had not made 
up his mind with certainty as to the stimulus 
which had revived it (i.e. whether it was pairing in 
water or the contact with the female). He did not 
allude to the stimulus in his lecture, and only with 
caution and reserve in his paper. The tight embrace 
necessary to hold a slippery partner seems to me, 
1 After consulting with Dr. Kammerer, it is obvious to me that Dr. Bateson 
mistook a patch of dirt adhering to the fourth finger of the specimen shown 
in these figures for the pad. 
