414 



VETERINARY PHYSIOLOGY 



trachea is connected with a pump and the lungs are thus 

 supplied with air so that the blood is oxygenated, (iii.) A tube 

 or cannula is tied into a carotid artery, CA., and it has a side 

 attachment to a mercury manometer to measure the arterial 

 pressure, M^. (iv.) The tube passes on to a very thin piece of 

 tubin^R., enclosed in a rigid walled glass tube, T., in which the 

 pressure can be raised to any extent which may be desired, 

 and may be measured by a manometer, M^. (v.) The tube 



Fig. 178.— The isolated heart-lnng preparation (the lungs are not shown). For 

 description see text. (Starling.) 



passes on and is provided with a by-pass, X., from which the 

 blood may be allowed to escape if the amount passed through 

 the heart is to be measured, (vi.) The blood passes through 

 an arrangement by which the blood is kept at body 

 temperature, (vii.) It returns to the superior vena cava, SVC, 

 and right auricle by a tube provided with a clamp so that the 

 amount entering the heart may be controlled, (viii.) The 

 blood then passes to the right ventricle, and so through the 

 lungs in which artificial respiration is kept up, back to 



