THE CARDIAC OR CORONARY VEI.\<. 599 



;i]>]K "iiunce. Remak found longitudinal muscular fibres in 

 tlic (// ntitlit of tho largo veins of the Ox and Sheep, but chiefly in tho 

 hepatic portion of the posterior vena cava and the veins of the liver.) 



K now "K i in: VKINS. To render th' disseetion and study of tho veins more easy, 



iirlit t > IT filled with tallow or any other solidiliable matter, like the arteries. Hut 



to iiit-iin this n suit tin- .-aim- mod-- .if |. ],,<, .lure cannot be employed as for them. 



lii>t'-:id of causing the injecting material to flow from the trunk into tin- bian. -lies, it is 



' propel it from the branches towards the trunk, because of the presence of 



tin- valv.s: this is to be done by successively fixing the canula into several venous 



l>ranehes. 



l-'.iur injections generally suffice to fill the whole venous system in a satisfactory 

 manner. The lir.-t is made from the alveolar vein, beneath the m:t t< r inii-rl,-; the 

 second from a digital vein of one or both anterior limb.*, or from the si<le of the foot, 

 alt- -i havinir .I'Mn-y.-.l by a stylet the few valves which are sometimes found tow;mls tli>- 

 !>>iiit of union in this vein ; or from the side of the heart. The third, from the posterior 

 digital veins, in the same way ; the fourth, by an intestinal vein. If any iin]x>rtant \ein.s 

 ;ii. empty after these four injections, a case of frequent occurence, they can be directly 

 iujed 



CHAPTEK n. 

 VEINS OF THE LESSER CIRCULATION, OR PULMONARY VEINS. 



THE pulmonary veins comport themselves in the same manner as the 

 corresponding arteries. They are lodged in the substance of the lung (com- 

 mencing in the capillaries, upon the walls of the intercellular spaces and air- 

 cells, joining to form a single trunk for each lobe), and collect in from four 

 to eight trunks, which open into the roof of the left auricle, after emerging 

 from the pulmonary organ immediately above the origin of the bronchi. 

 As they are destitute of valves, they readily allow the blood to flow towards 

 their roots. It is they which carry to the left heart the fluid thrown into 

 the lung by the right ventricle, to be submitted to the revivifying influence 

 of the atmosphere. 



CHAPTER IH. 



V KIN'S OF THE GENERAL OR SYSTEMIC CIRCULATION. 



THESE vessels bring to the right auricle the blood which has been dispersed 

 in the texture of organs, by the ramifications of the great arterial tree. 



They open into tho auricle by forming three groups : the group of 

 coronary or cardiac veins ; the anterior vena cava, and the posterior vena cava. 



ARTICLE L CARDIAC OK CORONARY VEINS. 



There are several small, and one large or great coronary vein. 



SMALL CARDIAC VEINS. These are tho almost insignificant vessels, un- 

 determined in number, which come from tho walls of the right ventricle and 

 open directly into the corresponding auricle at tho coronary groove. 

 (Amon; thes<' may bo included tho debatable rense Thebetii, a multitude of 

 minute venules said to arise in tho structure of tho heart and open directly 

 into its cavities.) 



GREAT CORONARY VEIN (Figs. 258, 5 ; 259, o, j>). This vein is formed 

 by two roots : one is lodged in the right ventricular groove, and accompanies 



