INTIMATE ASSOCIATIONS OF INORGANIC IONS, ETC. HARRIS. 77 



But, further, the salts of the diet must be present in it in 

 their natural unions and not merely in a solution added to the 

 organic food. Whereas mice throve on a diet of dried cow's 

 milk, they were moribund in twenty to thirty days on the sugar, 

 fat and casein of milk to which a solution of the extracted salts 

 of milk had been added. We know that a diminution in the 

 amount of potassium absorbed will lead to scurvy. 



It used to be said that as the salts contribute no energy, 

 they are not incorporated into the living matter; this is quite 

 a mistake, for although they do not yield energy, they are incor- 

 porated as truly as is the fat or carbohydrate or oxygen. It 

 would appear that all the following must be present in the tissues 

 and fluids, not necessarly all in all : sodium, potassium, calcium, 

 magnesium, iron, phosphorus, chlorine, iodine, fluorine and 

 arsenic. Without these, the living matter is not functionally 

 intact : there is a metabolism of the inorganic as truly as there 

 is of the organic. 



Take the case of the beating heart; if perfused with dis- 

 tilled water, even containing oxygen and dextrose, it will shortly 

 stop beating, and a loss of salts from it can be proved to have 

 occurred. Now give it a perf us ion-fluid with sodium chloride 

 whose osmotic pressure is equal to that of the sodium chloride 

 in the heart, and still it stops. This is found to be because we 

 have left out the potassium and the calcium ; the addition of 

 these, the potassium chloride as dilute as 1 in 10,000 is enough, 

 will cause the heart to beat rhythmically. Apparently the cardiac 

 myoplasm establishes an equilibrium between certain organic 

 ions within itself and others in the lymph of its spaces, the 

 point of equilibrium being dependent upon the osmotic pressure 

 of these substances in the surrounding fluids and on the affini- 

 ties of the protoplasm for these substances. If any one ^u 

 predominates somewhat over the others, that is, is present in 

 higher concentration than exists in normal lymph, effects which 

 have been called "toxic" will supervene; thus if potassium is 

 too abundant we have the heart stopping in potassium diastole, 



PROC. & TRANS. N. S. INST. Sci., VOL. XIII. TRANS. 6. 



