Referate. 



361 



writers in the widest possible sense. It is doubtful whether it will help to 

 remove the confusion which at present exists, to include under one term 

 complete absence of pigment, general or local reduction of pigment, and 

 the condition which may be described as piebalding, but the mass of facts 

 collected, even though they belong to what are probably very different 

 categories, cannot fail to be of value to all investigators of the object. 



The first section (Chapter VII) is devoted to the Albinotic eye in Man. 

 It is shown that all stages of reduction of pigment are found, both in the 

 mesodermal and epidermal pigment layers, but that, except in the case of 

 one young infant, there is no recorded case of complete absence of pigment 

 from the retinal epithelium. The completely non pigmented eye, such as 

 exists in true albino mice, is therefore possibly nonexistent in Man. The 

 vision of the albino eye, and its relation to Nystagmus and other defects, 

 is fully dealt with. 



In the chapter on albinotic hair, it is concluded "that albinism of the 

 hair is as widely diverse in character as albinism of the eye . . . ." The 

 snow-white hair of a clinically complete albino may contain a few pigment 

 granules, and the hair of normal persons (especially red or yellow hair) 

 may have none, but only diffuse pigment. There is no complete correlation 

 between albinism of the hair and eyes, and there appears to be distinct 

 tendency for red hair to be frequent in albinotic stocl^. 



A long chapter is devoted to a description of eyes with deficiency of 

 pigment in animals, ranging from total absence to the wall-eye, which 

 corresponds most nearly to the blue eye in man. This is followed by a 

 very interesting section on the seasonal variation of animals which turn 

 white in winter. Specimens of the Variable Hare were kept alive over a 

 considerable period, and the manner of the change closely watched. The 

 result is "all in favour of the view that both the vernal and autumn 

 changes are associated with falling off of old hairs and the appearance of 

 young shorter hairs which are pigmented at the vernal change and white 

 at the autumn change". Confirmatory evidence in given from the Stoat. 

 There is no satisfactory evidence that the pigmentation of the eyes varies 

 with the season. 



The last chapter deals with breeding experiments with an albinotic 

 strain of Dogs (Pekinese), and is the least satisfactory in the volume. The 

 writers sum up the results by saying "We have learnt enough to be sure 

 that no simple form of Mendelian theory applies to the inheritance of coat- 

 colour in dogs . . .'' By this is meant that the somewhat complex results 

 obtained cannot be explained on the assumption that one pair of characters 

 only is involved. No attempt is made, however, to analyse the factors 

 which are concerned. 



The Atlas of Part II contains 31 beautifully executed plates, several 

 of them colour. Part IV consists of an Atlas of nearly 700 pedigrees on 

 59 plates, with a volume of descriptive text and bibliography. To the 

 investigator this is probably the most important part of the whole mono- 

 graph, for the descriptions are very full, and supply a most valuable source 

 of information on the heredity of many forms of deficient pigment. A 

 glance at the pedigrees shows that as far as inheritance is concerned, 

 several quite distinct conditions are grouped together as 'albinotic'. Several 

 pedigrees of total albinism show a descent suggesting a typical Mendelian 

 recessive; a white lock of hair is equally clearly a dominant feature. In 

 many cases, especially when partial and complete albinism occur in the 

 same family, there are irregularities which would make any generalization 



