112 BOARD OF AGRICULTURE. 



often the case, it appears in the form of several tumors, there 

 may be a number of tumors upon the tail, under the jaw, and 

 probably in the internal cavities. That fact struck me as rather 

 a curious one, as seeming to show some inherent weakness which 

 may be indicated by the color. 



Professor Agassiz. I may say a few words upon the origin of 

 these changes of color in some animals, which will show that 

 such changes cannot take place without a very important modi- 

 fication of the general functions of circulation and secretion. It 

 is best exemplified in the cat. The cat, in its natural condition, 

 is gray ; but if you examine the hair of a single individual, you 

 will find that that gray color is not produced by a uniform gray 

 tint spreading over the whole fur, but by every hair being alter- 

 nately ringed with black, white and russet color. Each hair has 

 these colors in rings alternating with each other, the black rings 

 being more numerous near the root of the hair ; so that when 

 you open the hair and look at the base it will appear as if it was 

 thoroughly black, and if you look at the tip it will appear 

 almost perfectly russet, because the reddish hair is more 

 numerous near the tip. There is about an even mixture towards 

 the middle of the hair. That is the case, to a very singular 

 extent, upon the surface of the body of a gray cat, or of the cat 

 in its normal condition. Now, what are tri-colored cats ? They 

 are cats that have patches of white and black and russet hair 

 upon their bodies. A white cat is one from which the coloring 

 matter has been taken away from her hair and is now deposited 

 in her eyes and paws and in the margin of the lips. So it is 

 with the black cat, in which the white passes into the eyes, the 

 paws, the intervals between the jaws, and so on. There must 

 therefore be modifications of the secretions of coloring matter 

 among cats, so that in one case it shall be divided in a regular 

 ratio on each single hair, and in another case divided among 

 particular parts of the body. It is impossible that such changes 

 should go on without considerable effect upon the condition of 

 the skin, and in consequence of that, upon the general condition 

 of the animal ; but what that effect is, I do not know. I cannot 

 believe that animals of the same species can exhibit widely 

 different varieties of color without exhibiting at the same time 

 concomitant differences in other respects ; and in order that this 



