296 PHYSIOLOGY CHAP. 



by all who have taken up this subject. Einger's solution 

 consists of 



100 c.c. of ;i 6 per cent solution of XaCl 

 1 1 XaHCO, 



1 ,,1 ,, 



0-75 1 KC1 



Locke (1895) showed by new work that the addition of a small 

 quantity of glucose to Einger's solution rendered it more capable 

 of maintaining cardiac activity. 



Gbthlin, under Oehrwahl's direction, has recently (1902) 

 carried out some detailed experiments on the chemical conditions 

 of cardiac activity in the excised heart of the frog. He prepared 

 a complex solution of mineral substances, including all those 

 which chemical analysis has shown to be present in blood serum, 

 in the following proportions : 



Nad . . 0-65 percent. (.'1 . . O'Ol percent. 



NaHCO, . . 0-1 UaClo . . 0-0065 



Na 2 HP0 4 0-0009 XaH,P0 4 0-0008 



He found that on replacing the blood by this solution cardiac 

 activity was maintained unaltered for many hours. The pro- 

 portions in which the different salts enter into solution are by no 

 means unimportant. On substituting Einger's solution for the 

 above, both rhythm and type of beat were modified. Gothlin 

 further saw, on preparing solutions in which one or other of the 

 constituents predominated (with the object of determining the 

 influence of each upon cardiac activity), that the results indicated 

 all to be more or less necessary to its maximal prolongation. 



In a second series of researches he proposed to determine on 

 what the great difference between the survival period of a heart 

 treated with his solution, composed solely of inorganic substances, 

 and that of a heart treated with normal blood, depends. As regards 

 the importance of the erythrocytes and of haemoglobin the fact he 

 discovered is worth noting, that a haemolytic fluid (i.e. one which 

 contains dissolved haemoglobin) is injurious rather than beneficial. 

 He explained the toxic action of this dissolved haemoglobin to 

 consist in its combining with the lime-salts of the serum, so that 

 they are removed from the heart, which requires lime salts electro- 

 lytically dissociated in the form of Ca-ions. In fact, he found that 

 the subsequent addition of lime salts renders haemolytic blood 

 innocuous. 



In other experiments he found that after weakening the heart 

 with his saline solution, he could restore its activity by perfusing 

 it with a new complex solution consisting half of serum of ox 

 blood, half of the saline solution. He concluded that serum must 

 contain a substance capable of exerting this beneficial action 

 on the heart, and proposed to ascertain experimentally which it 



