292 



PHYSIOLOGY 



CHAP. 



conditions, without special treatment, it speedily ceases ti. beat;. By 



nt' ;i raiinula tied tn 

 t lie aurla, in the din-r- 

 tioii of the heart, lie 

 caused Mood or other 

 nutrient solutions in 

 circulate at a tempera - 

 ture of 38 C. under a 

 pressure corresponding 

 to the normal pressure 

 of the aorta, The fluid 

 ki-eps the semilunar 

 valves closed, circulat- 

 ing through the coron- 

 ary system ol'the heart, 

 and flowing out again 

 through the opening in 

 the right auricle. The 

 cardiac cavity remains 

 empty. A heart thu.- 

 artihcially fed is cap- 

 able of continuing its 

 activity almost nor- 

 mally for many hours. 

 The graphic record of 

 its movements can be 

 taken by means of sus- 

 pension, or (after oe- 

 Fif,. l-Jt5. Engelmann's myograph for refolding beats of frog's eluding the veins of 

 heart in sitv, when suspended from the apex by a thread f.] lt i right auricle) by a 

 connected with a highly sensitive lever. The apparatus is a 1 ]' * 



two-armed lever, one arm of which is attached to a fine silk manometer app 

 thread, the other to a long straw or strip of aluminium, which the pulmonary artery 

 magnifies the movements of the writing point on a smoked 

 surface. At the end of the thread is a fine glass hook, with 

 sharp point, which is inserted into the tip of the apex, after 

 cutting the fraennm by which the two layers of the pericardium T T rpi 



are united dorsally. L lle 



it is possible to keep 



the isolated heart of different animals alive for a comparatively 

 long period has been used as the start- 

 ing-point for a series of researches on the 

 nutritive medium, or external chemical 

 conditions, necessary to its survival. 



This work has familiarised us with 

 the so-called physiological solutions, 

 which are artificial nutrient fluids, 

 capable (at least for a certain time) of 

 replacing the blood, since they contain 

 all the elements necessary for sustaining FIG- 1-27. cardiograms taken from 



,. i-f ,> ,-, -i m, tVug l>v Kngelmann's method, a, 



the hie ol the heart. Ihe importance commencement ..f ventricular 



of this Sllhl'ppt PVPPPflq HIP limits of thp systole (Fs); I, commencement of 



auDje< exceeas cue limits oi uiie diastuie(iv): ,-, curves O f a tuning- 

 present chapter, for it may logically fork whir]l viin-ates 10 times |..-, 

 be concluded that artificial fluids which 



are capable of sustaining the vitality of the excised heart will 

 also maintain the vitality of other organs or isolated tissues, or are, 



