OF THE MUSCULAR SYSTEM IN GENERAL. 413 



mitive fibres, which require, in order to be seen, to be magni- 

 fied about 300 times; their observations therefore relate only 

 to secondary fibres. 



Hooke observed that the muscles of many animals are com- 

 posed of an innumerable quantity of fine threads, the volume 

 of which he estimates at the hundredth part of a hair, and 

 compares its figure to that of a series of pearls or beads of 

 coral. Leuwenhoeck, after having perceived the muscular 

 fibres, which he calls primitive, conjectured that they were 

 again composed, founding his idea, though incorrectly, on 

 the supposition that spermatic animalcules, still nrore minute 

 than fibres, must be provided with nerves and with mus- 

 cles; he moreover delineated rough figures of them; those of 

 Dehayde, though coarse also, are more exact. Muys has 

 given descriptions of them equally long and exact, he repre- 

 sents them as most generally cylindrical, and seldom knotty. 

 De la Torre says they are reddish, which is not generally 

 true. The observations of Prochaska, which are much more 

 exact, prove that these fibres are parallel but not always 

 straight, and that in cooked flesh they are almost always flexu- 

 ous; that their form is not cylindrical, but flat and prismatic; 

 that their substance is diaphanous and appears to be solid; their 

 diameter, with little variation, appeared to him to be seven or 

 eight times less than the largest diameter of a red globule of 

 blood. This observation, however, seems to be inaccurate; 

 he considered these fibres as constituting the ultimate degree 

 of the division of the muscles, without going so far as to affirm, 

 however, that these are the elementary fibres. The micro- 

 scopic observation made by the brothers Wenzell, on a por- 

 tion of muscle previously immersed during eight days in a 

 mixture of alcohol and muriatic acid, discovered to them that 

 each fibre was composed of round and minute corpusculi. Ac- 

 cording to M. Autenrieth, the diameter of these fibres is the 

 fifth of that of the globules of the blood. M. Sprengel, on the 

 contrary, estimates the diameter of the muscular fibre at seven 

 times that of a globule of blood, (which is the three hundredth 

 part of a line) that is to say, at about the fortieth part of a line; 

 he moreover describes it as angular, striated and full. The 



