INHERITANCE OF COAT-COLOR IN CATS 559 
either on chromogen or on yellow pigment. Combined with 
enzyme | it oxidizes chromogen to sepia. 
The agouti factors are considered as determining an inhibi- 
tor of enzyme 2. ‘Factor A determines the production of an 
inhibitor with the same subtraction effect on enzyme 2 every- 
where.” This inhibitor acts in waves along the individual hairs. 
The regions of greatest concentration determine the yellow 
bands, while those of less concentration are black. 
In yellow eats it is seén that banding occurs over the surface 
of the body, straw-color alternating with orange. Banding, 
therefore, affects enzyme 1. In black cats the bands are almost 
indiscernible. There is, then, enough of enzymes | and 2 gen- 
erally distributed to produce a uniform black. In the presence 
of the agouti factor, however, yellow bands appear in the indi- 
vidual hairs. These bands are much wider in the areas corre- 
sponding to the straw-colored bands of yellow cats. In fact, 
the black may be here entirely obliterated. The hairs in the 
areas corresponding to the orange bands of yellow cats are much 
darker and may be without apparent ticking. It therefore ap- 
pears that the banding factors affect enzyme 2, for if enzyme 2 
were uniformly distributed as in rodents, the agouti factor should 
cause a uniform ticking over the body surface, not an alternation 
of dark and light bands. 
The banding factors may be thought of, then, as determining 
waves of general metabolic activity affecting both enzyme | and 
enzyme 2. In the black cat the regions corresponding to the 
orange bands in the yellow cat would be a dense black, a sort of 
black dominant to agouti, comparable to Punnett’s (12 and 715) 
dominant black in rabbits, while the regions corresponding to the 
straw-colored bands would be comparable to ordinary black in 
being recessive to agouti. 
For helpful criticism and discussion of these matters I am 
much indebted to Dr. Wright, whose papers I have already 
mentioned. 
