Of the mufcuhr Fibres of Animals . 27 
Of the.mufcular or flefhy fibres of animals. 
M R. Leeuwenhoek hath difcovered each mufcu- 
lar fibre to be made up of fmaller fibrils, which, 
notwithstanding their fmallnefs, he plainly difcern’d to 
be vafcular, for on cutting a-crofs their length, the 
light might be feen through their apertures; but if he 
■cut them ever fo little obliquely, could fee no light. 
He alfo obferved the ftrudfure of the fibres in the flefh 
of an ox, and of a whale, but plainer in that of a 
whale j the fibres of the other being more compact and 
clofe; and found alfo that the fibres of a moufe were 
of the fame fize as n thofe of an ox; from whence he 
concludes, the different fize of animals is entirely ow¬ 
ing to the number and length of their fibres. Thefe 
flefhy fibres appear throughout their whole length, to 
be encompaffed as it were with fpiral circumvolutions 
as is exadfly reprefented in fig. 6 q. 
Which difpofition feems to be wonderfully contrived 
for readinefs in the diftenfion and contra&ion of the 
fibres. Two of thofe flefhy fibres are reprefented by 
G H, and I K, fig. 68. 
To view the mufcular fibres with the microfcope, 
cut off a piece of dried flefh or fifli, as thin as poffible, 
and lay it upon a glafs flip, and moiflen it with warm 
water, which drying foon away, will leave the velfels 
open and diftinguifhable. As the learned differ in 
their opinions with refpeft to' the figure and ftru&ure 
of thefe little veficles, I fhall leave it to the curious 
for farther examination. 
Mr. Leeuwenhoek informs us, that the flefhy fibres 
in infers are no lefs vifible than thofe of larger crea¬ 
tures, 
11 Arc. Nat. Tom. iii. p, ic8. 
