512 GEORGE E. HOLM AND JAMES M. SHERMAN 



order of effects may be reversed when changes take place in 

 acid or in alkaUne solutions, but the sequence usually remains 

 the same. 



The lyotropic effects of salts upon compressibility, surface 

 tension, solubility, etc., of organic and inorganic substances in 

 solution is not great in most cases. It is in the field of colloid 

 chemistry that these effects attain a magnitude of great signifi- 

 cance. A review of the literature covering this field is out of 

 the question here, but a few citations from the biochemical 

 field will serve to show the reasons for extending the work to 

 the field of bacteriology. 



In view of the recent and extensive investigations of Loeb 

 (1918-1921) upon the physical and chemical properties of pro- 

 teins it will probably be necessary to modify certain conceptions 

 now held concerning the relative magnitude of various ionic 

 effects in protein solutions. As to whether the Hofmeister 

 series of ions will be shown to be entirely a delusion, as is believed 

 by Loeb, we do not care to express an opinion, and it is not the 

 purpose of the present paper to take sides on that controversial 

 question. 



Whatever may be the status of ion effects in protein chemistry, 

 specific ionic effects in biological phenomena have been well 

 established by the work of Loeb and many others. It is our 

 purpose to study systematically salt effects, especially the quali- 

 tative and quantitative relationships of radicals (anions and 

 cations), as related to bacterial growth, and to correlate these 

 findings with other effects which have been noted in pure chem- 

 istry as well as in biology. 



Closely related to the phenomena of hydration and coagulation 

 is that of permeabiUty and diffusion. On the basis of the view 

 of Bechhold and Ziegler (1919) that membranes do not act Uke 

 sieves, but as though they were a network of arranged ions, it 

 is easy to conceive of enormous salt effects upon permeability, 

 both by influence upon ions which are to diffuse and by effects 

 upon ions forming the membrane network. 



Bacteria perhaps represent matter in a state as near the state 

 of colloids and also as near the state of living protoplasm as 



