BREEDING AND CROSSING FOR COLOUR. 



11 



the same with all faults of form — a judicious course of selection of 

 male and female will soon show its effects, by remedying the evils 

 which it is desired to eradicate. 



More difficulty will be experienced in fixing the various colours, as 

 the tendency to revert is so very great, where care has not been 

 taken to keep the blood pure for several generations, the colour often 

 revertiog in a perfectly bewildering manner. Indeed, at times one 

 feels inclined to believe that the animals are almost like the chameleon 

 — able to change colour at will. For self colours, the best plan is to 

 obtain all the coloured mice in pairs (a buck and doe), and keep 

 them distinct in separate cages, so that the colours shall be kept pure. 

 In three months the first litters will be old enough to breed from, 

 and if only a small stock is required, put separate pairs together in 

 the small cages previously described. These pairs should be selected 

 to produce piebalds, or two-coloured animals, and care should be 

 taken always to pair the same colours at other times ; as, a plum 

 buck and white doe should always be paired to others of the same 

 colour, for, strange as it may appear, if a white doe throws a litter to 

 a plum buck, if afterwards placed with a sandy buck, some of the 

 young from the cross are almost sure to show plum markings. In 

 fact, the colours of previous crosses show themselves more or less 

 throughout the whole life of the different litters obtained. 



Silver grey is obtained by crossing a very light black (if we may 

 be allowed the term) buck with a white doe, or vice versa ; or by 

 crossing very light plum or grey with white, and then crossing the 

 lightest colour obtained with white for two or three generations. 

 It is, however, useless to cross piebalds for this purpose, and at aU 

 times the results are not certain. 



Black and white is obtained by crossing the two colours together. 

 The same for any two combinations of colour. In this class the 

 more evenly the animals are marked the better, as uniform markings 

 are the prettiest. To secure a continuance of uniform markings, 

 choose two that are marked nearly or quite alike, and continue to 

 breed from the best of the young ones so obtained. By careful 

 selection and constant care in this direction, strains can be obtained 

 that will throw a large percentage of young ones marked like the 

 parents. Some of the forms of marking previously described are 

 very handsome, and are, moreover, very saleable, paying well for 

 the trouble of selection. 



To obtain tri-coloured mice two crosses are necessary : crossing a 

 coloured mouse with a piebald or other colours, or crossing two 

 piebalds together, as fawn and white with black and white, which 

 produces tortoiseshell, though rarely. In these crosses it is very 

 often the case that piebalds are produced, instead of three-coloured 

 animals ; and sometimes, as we have experienced, black, fawn, white, 

 black and white, and fawn and white are produced in one litter ; 

 on more than one occasion we have had two tortoiseshells in one 

 litter. Tortoiseshells, or other tri-coloured mice, paired together, 

 generally produce the greater percentage of animals coloured like 

 the parents, especially if they have been bred in-and-in for several 



