22 TIUCHOLOGIA MAMMALIUM; 



by the union of as many filaments. We find them chamfered, but that they are formed 

 by the union of 20 or more filaments, we are unable to confirm, and yet would not like 

 positively to deny. We made many transverse sections, which were examined under the 

 microscope, with the view of ascertaining if any such union exists. Sometimes, especially 

 where the section is made in the neighborhood of the furcation, separate portions of the 

 shaft may be seen ; but they are not homogeneous in shape, as it seems to us they ought 

 to be if they were an union of filaments ; but, on the contrary, have the appearance of the 

 fibres of other furcated pile. We separated one bristle throughout, into as many portions 

 as there were furcations. Upon exposing these to view under the microscope, the sides 

 that had been exterior could easily be detected by their smooth appearance, while those 

 that were originally the interior were covered with ruptured fibrils. (See fig. 14.) 



Cuvier says, also, that each bristle has two canals, one for the marrow and the other a 

 humor. We could not find them. 



EXAMINATION AND DESCRIPTION OF A BRISTLE OF A RUSSIAN WILD BOAR. Length 9^ 

 inches ; diameter -fa of an inch. Color of the button, brown ; of the shaft, white, and 

 transparent for the distance of 3 inches, and opaque for the rest. Button in length, T ^ T 

 of an inch ; diameter, ^ ; posterior termination, quill shaped ; shaft, chamfered. Apex 

 very much furcated. 



COMPARISON OF DIMENSIONS OF ELEVEN VARIETIES OF BRISTLES, SELECTED FROM OUR 

 COLLECTION. 



No. 1, French, black. Length, 11 ft inches. Diameter, -fa of an inch. 



white. " 13 ft " " ^ " 



" 2, 9ft ft 



" 3, Ohio, 6 T V & 



" 4, Russian, " 6 ft " " ^ " 



11 5, German, " 5 ft 



" 6, " " 5 



" 7, Ohio, " 4 ft " " r 



" 8, French, " 4 ft " " ^ 



" 9, Flanders,* " 3 ft " " T | T 



" 10, Wild Boar of Russia, " 9 " " ^ 



"11, Okakla of " " 5 ft " " 



From the above it appears that the French bristle is the longest, but that of Ohio is the 

 stoutest. 



Ductility, Elasticity and Tenacity of six Varieties. 



No. 1. One inch submitted to the trichometer May 28th, 1749. 



With 1,070 grains it stretched Jg- of an inch, elasticity entire. 

 " 4,466 " -> 



" 9,000 " ft " " 



" 10,000 " ft 



* Very much esteemed for paint brushes. 



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