414 



THE TISSUES. 



267. 



Transverse section of three fibres of 

 the dried pectoral muscle of the teal 

 (querquedula crecca), treated with weak 

 citric acid ; showing the round refract- 

 ing particles separated from one another. 

 The cut edge of the tubular sheath (in- 

 ternal perimysium) of each fibre is also 

 seen, as well as the capillary vessels (a) 

 in the intervals. 



The longitudinal vessels of the network lie between the fibres, and 

 the transverse ones unite in various ways with the former. Thus 

 each separate .fibre is surrounded on all sides by minute vessels, 



and hence abundantly supplied with 

 blood. The longitudinal vessels are 

 seen in a transverse section of a fasci- 

 culus (Fig. 267) lying in passages in 

 the internal perimysium. 



The capillaries of muscle are among 

 the smallest in the human body, their 

 diameter being often less than that of 

 the blood-corpuscles themselves. In 

 the pectoralis major, when filled with 

 blood, they measure g^ir to ^oVu of 

 an inch ; and, when empty, T gV to 



of an inch. (KoHiker.) 

 The tendons present no bloodvessels 

 in the innermost portions, and the 



smallest are entirely non-vascular internally. The latter, however, 

 present vessels in the sheath inclosing them ; and the largest have 

 vessels both in the sheath and in the deeper layers. (Fig. 176.) 



Very few lymphatic vessels are found in the muscles. Indeed, 

 the smaller (omo hyoid, subcrural, &c.), have none at all, either in 

 their substance or upon their surface ; and among the largest mus- 

 cles, it is only in some that solitary lymphatics, 6 V to ^g of an inch 

 n diameter, are seen accompanying the bloodvessels. It is proba- 

 ble that these do not run among the fasciculi, but in the more vas- 

 cular perimysia between the larger and laxer subdivisions; and 

 especially when the latter contains adipose tissue, and is therefore 

 soft, as in the glutaeus, and in the superficial layers of the muscles. 

 No lymphatics have yet been found in the tendons, aponeuroses, 

 or the synovial capsules of the muscular system. They may, how- 

 ever, exist in the areolar tissue under the latter ; as in the subse- 

 rous areolar tissue of the joints. 



Nerves of the Muscles. 



The nerves of the muscles come into contact with the fibres only 

 at a few points comparatively, and not throughout their length. 

 The trunks divide pretty suddenly on entering the muscles, into 

 several anastomosing subdivisions, which give off still smaller loops 



