Silk Manufacture. 281 



water. In common with the muscle, it has the power of spinning 

 a viscid matter from its body, in the manner of the spider and 

 caterpillar. Although the pinna is vastly larger than the muscle, 

 its shell being often found two feet long, the threads which it pro- 

 duces are much more delicate and slender than those of the mus- 

 cle, and scarcely inferior in fineness and beauty to the single fila- 

 ment of the comparatively minute silkworm. Threads so deli- 

 cately thin, as may readily be imagined, do not singly possess 

 much strength ; but the little power of each is made up by the ag- 

 gregate of the almost infinite number which each fish puts forth to 

 secure itself in a fixed situation, and to preserve it against the 

 rolling of the vv^aves. The threads are, however, similar in their 

 nature to those of the muscle, differing only in their superior fine- 

 ness and greater length. These fish have, therefore, been dis- 

 tinguished by some naturaHsts, the one as the silkworm, the other 

 as the caterpillar of the sea. 



' It was always well known that muscles have the power of 

 affixing themselves either to rocks or to the shells of one another, 

 in a very firm manner ; yet their method of effecting this was not 

 understood until explained through the accurate observations of 

 M. Reaumur. He was the first naturalist who ascertained that if, 

 by any accident, the animals were torn from their hold, they pos- 

 sessed the power of substituting other threads for those which had 

 been broken or injured. He found that if muscles, detached from 

 each other, were placed in any kind of vessel and then plunged into 

 the sea, they contrived in a very short time to fasten themselves 

 both to the sides of the vessel and to one another's shells : in this 

 process, the extremity of each thread seemed to perform the office 

 of a hand in seizing upon the body to which it would attach itself. 



' The threads issue from the shell at that part where it naturally 

 opens, and, in affixing themselves to any substance, form numer- 

 ous minute cables, by aid of which the fish steadies itself in the 

 water. Each animal is furnished with an organ, which it is diffi- 

 cult to designate by any name, since it performs the office of so 

 many members, and is the only indicator of the existence of vital 

 powers in the creature. It is by turns a tongue, an arm, and 

 sometimes a leg. Its shape resembles that of a tongue, and it is, 

 therefore, most frequently called by that name. Whenever the 

 fish requires to change its place, this member serves to drag its 

 body forward, together with its cumbrous habitation : in perform- 

 ing its journey the extremity of this organ, which may then be 

 called a leg, is fixed to some solid body, and being then contracted 

 in its length, the whole fish is necessarily drawn towards the spot 

 where it has fixed itself ; and by a repetition of these movements, 

 36 



