236 Mayow 



indeed, just as the fleshy fibres are inserted into the 

 tendons, so are the fibrils into the fleshy fibres, but 

 arranged the contrary way ; and as the fibres closely 

 joined together seem to form the tendons, so the 

 collection of fibrils seems, in part at all events, to 

 form the fibres themselves ; as is seen in Plate III., 

 Fig. 2, which shows the series of fibres and of fibrils, 

 as they are seen in muscles that have been boiled for 

 a suflSciently long time. 



Hitherto it has been held by the authors best 

 acquainted with anatomy that the fleshy fibres of the 

 muscle chiefly and primarily undergo contraction ; but 

 in our opinion (which I should wish to express with 

 all respect) not the fibres but the fibrils inserted trans- 

 versely into them, take the chief part in muscular 

 contraction, and this we gather from indications which 

 are at all events probable. For if the contraction 

 took place in the fleshy fibres, then, for a due contrac- 

 tion of the muscle, it would be necessary that the 

 fibres should be much more shortened than the 

 muscle itself; for as the fibres are not arranged 

 according to the length of the muscle, but are inserted 

 obliquely into the tendons, as may be seen in the 

 figure referred to, it follows that the contraction of 

 the muscle is much less than the contraction of the 

 fibres ; and that for a proper contraction of the muscle 

 it would be necessary that the fibres should be con- 

 tracted much more than the muscle itself: but I do 

 not think such a great contraction of the fibres really 

 occurs in motion : for, besides that we cannot in 

 vivisections see this sort of contraction of the fibres, if 

 the fleshy fibres contracted so much, the muscle 

 should swell enormously, but it does not. 



Besides, in order that the contraction of the muscle 

 should be effected by the fibrils, there is no need that 



