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POPULAR SCIENCE MONTHLY. 



Considering pigmentation and hair-length separately, we see, first, that 

 there are 12 pigmented animals to 4 albinos, or 3 to 1, as expected; 

 and, secondly, that there are 12 short-haired to 4 long-haired animals, 

 again 3 dominants to 1 recessive. But if we consider the relation of 

 each pair of characters to the other, we find absolutely no correlation 

 between them. Albinism may or may not be associated with long hair, 

 and pigmented coat may or may not be associated with short coat in the 

 offspring, though they were so associated in the grandparents. As a 

 matter of fact, when the animals are tested one by one, to determine the 

 presence of recessive characters, we find that albinism, visibly present 

 in 4 out of 16 offspring, is present recessive in 1 others, and that in half 



Fig. 10. A Long-haired, Smooth, Pigmented, Guinea-pig. 



of these cases it is associated with short coat, while in the other half it 

 is associated with long coat. 



In another experiment which I have performed with guinea-pigs, a 

 cross was made involving three pairs of alternative coat-characters, 

 length, pigmentation and roughness of coat. A long-haired rough 

 all )ino (Fig. 4) was mated with short-haired smooth pigmentefl animals 

 (Fig. 5). The young were all short-haired, rough and pigmented 

 (Fig. 6). The coat-characters seen in these offspring are the three 

 dominant characters, two of which were received from one parent, one 

 from the other; the three alternative recessive characters are present 

 but unseen. 



When the young were bred together, they produced offspring of 

 eight different sorts, including all possible combinations of the three 

 pairs of alternative characters. 



