OF THE MUSCLES. 89 



form the strands into ropes. The difficulty of the art has 

 been to make them bear aiike, especially in great cables, and 

 this has been the object of patent machinery. Tlie hardening^ 

 by twisting, is also an essential part of the process of rope- 

 making : for without this, it would be little better than ex- 

 tended parallel fibres of hemp. In this twisting, first of the 

 yarns, and then of the strands, those which are on the outer 

 surface must be more stretched than those near the centre ; 

 consequently, when there is a strain upon the rope, the outer 

 fibres will break first, and the others in succession. It is to 

 avoid this, that each yarn and each strand, as it is twisted or 

 hardened, shall be itself revolving, so that when drawn into 

 the cable, the whole component parts may, as nearly as possi- 

 ble, resist the strain in an equal degree ; but the process is 

 not perfect, and this we must conclude from observing how 

 different the construction of a tendon is from that of a rope. 

 A tendon consists of a strong cord, apparently fibrous ; but 

 which, by the art of the anatomist, may be separated into 

 lesser cords, and these, by maceration, can be shown to con- 

 sist of cellular membrane, the common tissue that gives firm- 

 ness to all the textures of the animal body. The peculiarity 

 ihere results merely from its remarkable condensation. But the 

 •cords of which the larger tendon consists, do not he parallel 

 to each other, nor are they simply twisted like the strands of 

 a rope ; they are, on the contrary, plaited or interwoven to- 

 gether. 



If the strong tendon of the heel, or Achilles tendon, be 

 taken as an example, on first inspection, it appears to consist 

 of parallel fibres, but by maceration, these fibres are found 

 to be a web of twisted cellular texture. If you take your 

 handkerchief, and, slightly twisting it, draw it out like a 

 rope, it will seem to consist of parallel cords; such is, in fact, 

 so far the structure of a tendon. But, as we have stated, 

 there is something more admirable than this, for the tendon 

 consists of subdivisions, which are like the strands of a rope ; 

 but instead of being twisted simply as by the process of hard- 

 ening, they are plaited or interwoven in a way that could not 

 be imitated in cordage by the turning of a wheel. Here 

 then is the difiference — by the twisting of a rope, the strands 

 cannot resist the strain equally, whilst we see that this is pro- 

 vided for in the tendon by the regular interweaving of the 

 yarn, if we may so express it, so that every fibre deviates 

 from the parallel line in the same degree, and, consequently, 

 receives the same strain when the tendon is pulled. If we 

 seek for examples illustrative of this structure of the tendons, 

 we must turn to the subject of ship-rigging, and see there how 

 the seaman contrives, by undoing the strands and yarns of 

 a rope, and twisting them anew, to make his splicing strong- 

 er than the original cordage. A sailor opens the ends of two 



