494 



A .H. Estahrook 

 Effect of Adding NaCl to the Distilled Water 



The effect of adding a small amount of some salt to the dis- 

 tilled water was next studied. For this purpose sodium chloride 

 was used. When enough sodium chloride was added to the dis- 

 tilled water to give a ^ J^Q solution, the results are those given in 

 Table II.4 



TABLE II 



Comparative measurements in microns of Paramecin on j^^NaCl dissolved in pure distilled water, and in 



hay infusion 



From this table it is evident that the addition ot the small 

 amount of the NaCl to the distilled water has a very good effect 

 on the vitality and growth of the animals. Most of them are alive 

 at the end of twenty-four hours. The growth is only slightly 

 retarded in the salt solution as compared with that in the hay 

 infusion. At the end of twenty-four hours, however, half the 

 animals in the salt solution were dead or dying. The living 

 specimensin the salt measured 18.48 X48.6 microns, and were thus 

 larger than the controls, which were 174.9 X54.9 microns. But it 

 must be noted that seven of the ten specimens that were in the 



* In this and the folio-wing tables, -whenever division has taken place, the figure enclosed in paren- 

 theses is the number of specimens at the beginning of the experiment, the other number indicates the 

 number of specimens at the end of the experiment. In this case there -were lo specimens at the begin- 

 ningof the experiment. These increased by division to 17 specimens at the end, allof which were 

 measured. 



