4 8



Correspondence , Notes , etc.



demonstration which we are justified in expecting, but of which I more than

doubt his ability, I shall certainly now take no part in it, although I shall be

present; but I have to-day (October 4th) arranged that it can take place in

the bacteriological laboratory where I am engaged in still further elucidating

this spurious tuberculosis, which is so common in most species of cage

birds and indeed in poultry, etc. as well. It is the laboratory of (Professor)

Hewlett himself.


If your readers will refer to my last letter on this subject (September)

they will realize the grave issues which hang on it, and will see in whom

their real friend is to be found.


W. Geo. Cresweee.


P.S.—I forgot to say that for the third time I challenge anybody to

demonstrate, etc.


[If Dr. Mylan cares to reply to the above his letter will be inserted in

our next issue, but otherwise this correspondence, which has already

become too heated and personal, is closed. Ed.].



MUTATIONS IN BIRDS.


Through the courtesy of Prof. W. E. D. Scott, I have just had

the pleasure of studying a most interesting paper recently published by

him in the new series of ‘Science,’ Vol. XXII., No. 557, pp. 271-282 (Sept.

1st, 1905)—“ On the probable origin of certain birds.”


The article treats of nine supposed species from North America and

one from Southern Europe; and from the fact that seven of these are

either only known from individual types or from illustrations, he regards

them as probably mutations from known species which have failed to

establish themselves as permanent distinct species.


The two other North American species appear to be on the increase;

and, from the evidence of field-naturalists are proved to be, in Prof. Scott’s

opinion, separate and distinct mutations from a common parent stock.


The European species (Athene chiaradece ) is also regarded as an

instance of neogenesis and not of teratological or pathological origin.


I11 my “Foreign Finches in Captivity” it will be remembeied that I

expressed the opinion (p. 178) that the Red-lieaded race of the Gouldian

finch was a mutation from the Black-headed race and was 011 the increase

owing to the preference shown by the hens of both types for the Red¬

headed males, and that eventually the Black-lieaded race would become

extinct. Recent evidence furnished by breeders is entirely favourable to

this view; black-lieaded parents producing young with red heads. Un¬

fortunately, owing to the tendency 7 of the hens to egg-binding, successes in

breeding this species in captivity are not so frequent as in the case of some

other Australian finches, but much may be done by keeping the birds onl\ r

in open air aviaries.



