368 THE POPULAR SCIENCE MONTHLY. 



it a long time, had it not moved, before I would have noticed it. I 

 called the attention of the captain of the ship to the object, and he ex- 

 amined it for some minutes, the crab not moving, before he saw any- 

 thing but bark. How came this brown crab, on a piece of wood of 

 precisely the same color, in the middle of the ocean ? Must we believe 

 that sevei'al crabs got oji the bark, among them the brown one, and 

 that the struggle for existence resulted in his being the only one left ? 

 I am satisfied that we can come to no other conclusion than Wagner's, 

 and that we must believe that a conscious or perhaps an instinctive 

 choice governed the animal in settling upon an object so like it in 

 color. The bark was probably occupied while floating among the sea- 

 weed, then drifted away to the spot where it was found, and where it 

 furnished so singular an isolated example of selective mimicry. I 

 found numerous slender fishes in the algae of the Sargasso Sea, like- 

 wise protected by their resemblance in color to the plants among which 

 they lived. One afternoon, after I had examined a plant for an hour 

 for crabs, I took it out of the pail to throw it into the sea, when a fish 

 about the size of a lead-pencil fell out of it. I put the fish into 

 another pail, in which there was also a sea-weed. It instantly van- 

 ished from my sight, and I had to look for some time among the thick 

 stems before I could find it again. 



I do not know whether any of these observations have been re- 

 corded before. During my residence in Brazil, I had but limited op- 

 portunities to keep acquainted with recent zoological literature. But 

 I found my sail through the Sargasso Sea full of interest, and I be- 

 lieve that a voyage there would be fraught with pleasure and profit 

 to every naturalist. It is not so very expensive, either ; and can easily 

 be made on a schooner or bark sailing from a European port to the 

 West Indies. My passage from Porto Allegro in Southern Brazil, to 

 Falmouth, England, from the 15th of June to the 25th of September, 

 cost me, board included, less than seventy-five dollars. Such a voy- 

 age furnishes, moreover, at the same time, an opportunity to make a 

 personal acquaintance with the natural history of tropical regions. — 

 Tramlatedfor the Popular Science Monthly from Kosmos. 



THE CHEMISTEY OF COOKEEY. 



By W. MATTIEU WILLIAMS. 

 XLII. STIMULANTS ANT> CONDIMENTS. 



BEFORE proceeding further, I must fulfill the promise made in 

 No. 39 to report the results of my repetition of the Indian pro- 

 cess of preparing samp. I soaked some ordinary Indian corn in a 

 solution of carbonate of potash, exceeding the ten or twelve hours 



