ION-PROTEID COMPOUNDS 549 



address of ion-proteid compounds, and I only need to quote 

 the following sentence in order to show how far his concep- 

 tions and mine agree. "We cannot doubt the general 

 existence of ion-proteid compounds in the living organism. 

 We have even urgent reasons for assuming that all the pro- 

 teids of the protoplasm exist there only in combination with 

 ions." I shall have a chance to discuss his views further 

 when the full account he promises of his experiments appears. 

 These introductory remarks may suffice for the present. 

 I will now report on a series of experiments which were 

 undertaken 011 the assumption of the existence of ion pro- 

 teids, and the possibility of changing the qualities of tissues 

 by changing the relative proportions of ions in the tissues. 



II. EXPERIMENTS ON FISH 



If it be true that life-phenomena depend upon the pres- 

 ence of a number of various metal proteids (Na, Ca, K, and 

 Mg) in definite proportions, it follows that solutions which 

 contain only one class of metal ions must act as a poison. 

 The reason for this is that the one class of nietal ions will 

 gradually take the place of the other metal ions in the ion 

 proteids of the tissues. Even a pure NaCl solution must 

 thus be poisonous, although this salt permeates all our tissues 

 and is the main constituent of the inorganic matter of the 

 ocean. I have looked through the literature in vain to find 

 facts which corroborate this view. I found only the follow- 

 ing data: Ringer and Locke 1 mention the fact that in NaCl 



o ~ 



solutions the contraction curve of a muscle may show slight 

 variations, and Locke adds that the same is true for certain 

 electric phenomena in the nerve. True has added another 

 observation in this direction. It has been known for many 

 years that if we put plant cells, for instance Spyrogyra, into 

 a very concentrated solution of salts or sugars, the cells 

 lose water and cease to grow. True found that the osmotic 



1 LOCKE, Archivfiir die gesamtnte Physiologie, Vol. LIV (1893), p. 501. 



