•294 



Mr. S. G. Paine. 



[July 12, 



of the latter plasmolysis was well marked, the effect increasing with 

 increasing concentration. Since no appreciable effect is produced by con- 

 centrations up to 10 per cent, it seems possible that diffusion of alcohol is 

 freely permitted. The plasmolysis produced by more concentrated alcohol 

 may be a result of changes in the molecular constitution of the protoplasm. 

 Comparison with the case of mercuric chloride tends to strengthen this 

 view. 



The liability to plasmolysis by 20 per cent, alcohol exhibited by different 

 samples of yeast seems to vary with the physical condition of the yeast. 



In the experiments given in Table III 10 grm. of pressed yeast were 

 stirred up with 20 c.c. solution, allowed to stand over night in the cold room, 

 and centrifuged next morning. 



Table IV. 





Yeast A. 



Teast B. 



Yea 



tc. 



Yeast D. 



Yeast E. 























— 



Solution. 

























lume < 





If 













s = 









i 



£ & 





> * 



i 









1 



Water 



Alcohol, 5 per cent.... 



7 „ ... 



„ 10 „ ... 



„ 15 „ ... 

 „ 20 „ ... 

 „ 25 „ ... 

 „ 30 „ ... 



14-0 



- 

 14-0 



15 -0 

 17 -0 



- 



15-0 



14 -5 



15 -0 

 14-5 



14 -0 



15 -o 



14-8 

 14 -7 

 14 -6 

 14-5 

 14 5 

 14 "0 



155 

 16-0 



14 -5 

 15-0 



15 -0 

 15 -5 



14 -0 

 14-1 



13 -9 



14 -0 

 14 -1 

 14 '4 



13 7 



14 -1 



14 -0 



15 -0 



16 2 



16-1 



15 -7 

 15 7 



13 '8 

 13-1 



15-5 



15 -6 



15 -5 



16 5 



17 -2 



14 -3 



14 -0 

 13 -9 



13 -0 

 12 -6 



Yeast C was an old sample which had been kept in the cold room for 

 about 24 hours after being received from the brewery, and it is worthy of 

 note that no plasmolysis of this yeast by concentrations of alcohol up to 

 20 per cent, could be detected by this method. 



The fact that permanent plasmolysis of yeast is produced by higher con- 

 centrations of alcohol, by mercuric and cadmium salts which precipitate the 

 proteins within the cell, and by acids which prevent the activity of the cell, 

 shows that for this cell the existence of permanent plasmolysis is no criterion 

 of the non-diffusibility of the solutions producing it. 



In order to arrive at definite results on this subject, it was clearly seen that 

 quantitative estimations of the substance under investigation in the yeast- 



