178 THREADS OF THE BEARD. 



filaments, considering that each is finer than the 

 thinnest strand of silk, is remarkable. Their strength, 

 however, may be easily accounted for, when we know 

 that each is composed in reality of innumerable deli- 

 cate threads, bound together by a subtle gelatinous 

 fluid. This phenomenon may be made out quite dis- 

 tinctly with a common hand lens, if the following 

 simple experiment be adopted: Make a Mussel con- 

 struct its thread in such a way that the disc of each 

 is planted on the face of the glass. Then place the 

 fine point of a common needle upon the outer edge 

 of a chosen disc or sucker, and gently draw the 

 former away to a little distance, and you will find 

 that by so doing the stretched string becomes peeled. 

 Continue this process carefully, and before the thread 

 gives way you will have divided it into a dozen 

 parts at least, all of which are visible to the naked 

 eye, but clearer when the hand lens is used, and still 

 more distinctly and beautifully defined, of course, if 

 the microscope be brought into play. 



The foot of the Mussel appears to be firmly 

 strapped on, as it were, to certain transverse muscles, 

 by a contraction of which the animal closes its shell 

 with surprising force. This strap, composed of a 

 powerful tendon which passes under the adductor 

 muscles, is attached at either end to the base of the 

 foot. Thus we account for the remarkable strength 

 which is evidently seated in the foot, and makes 

 it of so much importance to the animal. At first 



