January 30, 1902] 



NA TURE 



297 



disease has been known on the continent for the last twenty 

 years, and notwithstanding that " Governments had taken up 

 the matter, " we are no wiser as to the life-history of the parasite 

 than they were in Germany at starting. Nor if we were should 

 we be probably any better off, however interesting the result 

 might be from a scientific point of view. For each phase of 

 such a fungus has apparently an indefinite capacity for propa- 

 gating itself independently. The rust of wheat is as destructive 

 in Australia as anywhere else, and is not checked by being 

 unable to complete its life-history on the barberry. 



It is not material, but it may be noted that Gnomonia 

 belongs to a group of fungi widely remote from the ru.st of 

 wheat. I can hardly believe that Mr. Carruthers intended to 

 suggest that they belonged to the same " class." 



But my object in drawing attention to the matter is to 

 remonstrate with my scientific friends for the mistaken policy 

 which it seems to me that many of them are too apt to adopt 

 in matters of this kind. It is the fashion now to clamour for 

 "State-paid" assistance for everything, with no sense of the 

 relative importance of the objects aimed at or appreciation of 

 the work which is actually being done. It is most important 

 that Government aid should be obtained for a definite purpose, 

 such as that of the National Physical Laboratory. But if 

 scientific men will not even give the Government credit for the 

 aid it gives, they run the risk of being regarded as impossible to 

 satisfy. 



In his report, published by the Royal Agricultural and 

 Horticultural Societies, Mr. Carruthers states: — " The neglect 

 of undertaking this operation (burning of the dead leaves), 

 though costly, means the disappearance of the cherry orchards 

 of Kent in a very few years." In the face of this very serious 

 statement it is remarkable that, so far as I can ascertain, no 

 information on the subject has reached the Board of Agriculture. 



Kew, January 22. W. T. Thiselto.\-Dyer. 



Variation in Fowls. 



Everyone wlio is acquainted with poultry must join Mr. 

 Tegetmeierin deprecating the economic degradation of good old 

 breeds by breeding for fancy points only (p. 152). But it is an ill 

 wind that blows nobody good, and from a scientific point of 

 view a decadent old breed with exaggerated points is more 

 interesting than one of the comparatively useful modern 

 mongrels produced by crossing, since the former shows con- 

 clusively what can be done by sheer selection, even though 

 applied for a senseless end. 



Fortunately, Mr. Tcgetmeier has given excellent comparative 

 views of some breeds before and after "improvement" in his 

 work on "Table and Market Poultry"; but if the old strains are 

 obtainable anywhere in their primitive form it would be, I 

 think, very desirable to get specimens and preserve them, 

 together with some modern highly-bred birds, for the benefit of 

 bionomical students when the declining breeds have become 

 extinct. Meanwhile, I should like to draw the attention of 

 students of variation to the great differences observable in 

 domestic fowls which have not been subjected to any selection, 

 such as the ordinary poultry of India. Among these, although 

 they are allowed to breed anyhow, may be seen all recognised 

 colours of fowls except those of the highly specialised laced, 

 pencilled and spangled breeds, which have needed a long course 

 of selection. Double or " rose" as well as single combs occur, 

 although the latter are a minority, and small crests are common. 

 Five toes and feathered legs are rare ; the legs vary much in 

 tin:. 



Now, in Egypt, I have observed that, while equally variable 

 in coloration, the fowls displayed some structural points 

 peculiarly their own. The combs are very often really double ; 

 not the coral-like "rose" comb, but a bifid or two-flapped 

 edition of the normal compressed and serrated form. The hind 

 toe also was very often bifid, exhibiting every gradation from the 

 five distinct toes of the Dorking to a distally split hind toe or 

 one in which the normal hallux was represented by a mere 

 terminal joint with a nail, growing from the long upper super- 

 numerary hallux. Indeed, I even got a specimen in which the 

 extra hallux alone remained, the true first digit having dis- 

 appeared altogether ! The consequence was that this bird's foot 

 looked like a curassow's, but I observed that it had very little 

 power of grasping therewith. 



In Zanzibar I again found poultry of every colour, but very 

 true to the lanky, close-feathered, small-combed Malay or 



NO. 1683, VOL. 65] 



Chittagong type, which thus seems to maintain itself in spite of 

 neglect by breeders. 



What is particularly noticeable in casually-bred poultry is the 

 correctness of some of the types of marking. Thus the silver- 

 grey variation, in the cock, resembles the typical black-breasted 

 red in everything except in that the red parts of the plumage 

 are changed to white. The corresponding hen has the brown 

 and yellow of the upper surface also replaced by white, and 

 hence is grey in tone with a silver-streaked hackle. 



When such correlated grey and rufous forms occur in wild 

 gallinaceous birds, they are put down as climatic variations, but 

 it is obvious that climate cannot be the <i^re^t cause, though it 

 may favour the survival of one type rather than the other, 

 according to constitution or surroundings. 



Another common style of marking found in two colours is 

 that in which the base of the neck, the primary quills and the 

 tail are chiefly black in both sexes, the rest of the body being 

 uniform, either white or some rufous shade ranging from bay to 

 buff'. This coloration might easily characterise a natural 

 species, although it is not known to do so ; in accepted breeds 

 the white form has been adopted as the proper colour for the 

 light brahma, and the cock of the golden-pencilled Hamburg 

 breed closely approximates to the black-tailed rufous form. 

 Hens of the black-tailed red type are, however, not recognised 

 in any breed. 



A very common and curious variation in rough-bred fowls is 

 the " wheaten " hen. This bird is of the pale-brown colour of 

 wheat, with a dark-brown neck and black tail; but the correlated 

 cock is a black-breasted red of the jungle-fowl colour. This 

 colour of the hen is recognised in Malays and old English game, 

 and is said to breed the brightest cocks. 



It has occurred to me that the occurrence of two such distinct 

 types of hens as the " wheaten " and the " partridge " (the name 

 given to hens of the jungle-fowl brown) in correlation with 

 similarly coloured cocks may, perhaps, help to explain the 

 phenomenon of dimorphism in female butterflies. For if we 

 knew the pedigree of these insects as well as fanciers do that of 

 their fowls we might very possibly find that in dimorphic 

 species two strains with dissimilar females but similar males 

 existed and interbred. 



So, also, the great and sudden variations throw light on the 

 origin of mimicry. The form of the fowl with white body and 

 black quills and tail, above alluded to, is similar in plan of 

 coloration to several large and powerful birds. If such a 

 variation occurred where the form and flight were favourable 

 to mimicry, as it might easily do among the multitudes of 

 passerine birds, we should have mimics ready-made. 



The problem in the case of butterflies is much easier, owing 

 to their greater general similarity of shape ; but in any case it is 

 obvious that variation is more important than selection here. 



Indian Museum, Calcutta. F. Finn. 



Elementary School Mathematics. 



The appointment of a committee of the British Association 

 on the teaching of elementary mathematics encourages the hope 

 that that body will be able, after collecting the opinions of 

 practical educators, to focus them with due wisdom into a scheme 

 which will be generally acceptable, both to teachers and ex- 

 aminers. For success to be attained it is obviously necessary 

 that those who are in actual touch with the work of teaching 

 should state what, in their judgment, is desirable and practic- 

 able. Hoping that others besides myself will follow the ex- 

 ample set some time ago by Mr. Hurst of Eton, I venture to 

 write to Nature a sketch of the conclusions to which an ex- 

 perience of many years at Charterhouse has led me. 



I have in mind in what follows the needs of the average 

 boy, not of that comparatively rare individual who has 

 some real mathematical taste ; but I am sure that the pro- 

 gress of the latter is at present often sadly retarded by the 

 course of study through which he is put. Our public schools 

 have, unhappily, as I think, no organisation for securing 

 common action except the annual conference of head-masters, 

 which has, so far, done very little for the cause of education, 

 hence methods and ideals vary much; but I shall assume that 

 the average character of what is taught may be gathered from 

 the papers set in the various public examinations for which we all 

 prepare, and from the most popular text-books in use. Taking 

 this ground, I think the broad indictment must be at once ad- 

 mitted that school mathematics are altogether too abstract and 



