1903.] IN FANCY MICE AND RATS. 77 



that colour may be influenced by structui^e, and structure by 

 colour, must be remembered. 



Naturally we may inquire whether albinism in Man is not a 

 similar recessive. Castle has given evidence pointing in this 

 direction. The occurrence of albinism in the families of first 

 cousins (see Day, Seligmann, &c.) is consistent with this view ; 

 but there ai-e a few I'ecoi-ded cases of the occurrence of albinos in 

 the offspring of albinos bi'eeding with normal parents, where the 

 hypothesis that the normal parent was DR is not at all easily 

 admissible. No case of the union of two human albinos is known 

 to me. The matter cannot here be further discussed, and the 

 reader must refer to the literature, the most important paper 

 being that of Cornaz*. 



There are a few cases on record where the production of albino 

 ofispring by animals and plants must almost cei'tainly be legarded 

 as the occurrence of a new and original variation, though the 

 cause of such sporting is entirely unknown. 



We here encounter the first problem calling for experimental 

 study. "What is an albino ? We know that it appears to form 

 no pigment; but such a body has other characteristics also. 

 While the blood of pigmented animals shows intravascular 

 clotting on the injection of nucleo-pi^oteids, that of the albino is 

 declared to be unaffected. The mountain hare is said in this 

 respect to behave as a normal in its summer coat, but as an 

 albino after the winter change. How these diflerences are 

 related to the want of pigment we do not know. Such an 

 inquiry offers a wide field for experiment. In pai-ticulai-, we 

 ought to know how the albino or the normal behaves towaixls 

 the nucleo-proteids of an albino, and so forth. However this 

 may be, there seems to be but little doubt that the albino-bearing 

 gametes can generally segregate that character entire, as they 

 divide from the colour-bearing gametes of the hybrid zygote 

 of any colour ; and if we knew more clearly what is the real 

 physiological difference between colour-secreting and albino 

 organisms, we might get a clearer conception of the nature of such 

 segregation. 



We may consider next the work of Crampe, which is on a 

 large scale and relates entirely to Rats. His latest paper is dated 

 1885 (10), and consequently is pre-Mendelian in treatment. He 

 bred nearly 14,000 rats, and made elaborate records and tables of 

 conclusions. Many of these observations are readily available 

 so far as they provide simply qualitative as opposed to quantita- 

 tive evidence ; but after many attempts I have not succeeded in 

 unravelling the material enough to group the statistics in Men- 

 delian form t. Though only a sketch can be here given, many of 



* The student of albinism who refers to the paper of Legrain (Bull. Ac. Med. 

 Bruxelles, ix. 1866) should remember that it is the curious instance cited by Darwin 

 (Life and Letters, i. p. 106) as a deliberate invention. 



t The figures given (10) pp. 555 & 612 are the likeliest, biit even these obviously 

 contain certain heterogeneous elements now not distinguishable with confidence. 



