68 Arber . — On the Effect of Salts on the Assimilation 
5. The maximum degree of concentration of sodium chloride 
is probably between 1 and 5 per cent. 
6. None of the other salts which form the principal con- 
stituents of sea water can take the place of Na Cl in any 
degree of concentration experimented with. The same remark 
applies to Na Br, Na 2 S 0 4 . 
7. The absence of any one of the principal salts in sea 
water other than sodium chloride, provided the others were 
present in the normal amounts, did not cause any inhibition. 
8. The presence of either Ca S 0 4 or K Cl in distilled water 
seemed to inhibit the carbon-assimilation almost completely, 
especially when in greater percentage than the normal 
amounts in sea water. 
