X. THE CHANGE OF PROTOPLASM STRUCTURE 



301 



the hydrated particles. 



It seems natural that sugars can penetrate when their concentra- 

 tions are high as shown in curves GI and FI ; but very strange 

 results are obtained if virus particles are used to which peculiar 

 manipulations were preliminarily added. Ordinary curves such as GI 



Cone, of the sugars, % . 



a5% 



Fig. 28. 



Sugar-impenetrable space of vaccinia particles. G = glucose, 

 F= fructose. 



Roman numerals indicate the No. of the preparations. 



and FI are secured when virus particles are used which were prepared 

 by merely washing with the water of a weakly acid pH without 

 neutralizing the acid after each precipitation. However, when the 

 experiments are carried out with the particles "purified" by repeated 

 precipitations with acetic acid, which is neutralized by NaOH after 

 each precipitation and centrifugation, the rate of penetration of sugars 

 is not always proportional to the concentration as shown in many 

 curves in the figure. Similar irregular results are yielded when the 

 particles are preliminarily heated to an adequate temperature. 



A mention will be made as regards the curve GUI in the figure, 

 which shows that when tlie sugar concentration is 0.06 per cent the 

 sugar-soluble space takes a negative value, indicating that the sugar 

 concentration in the particles is higher than that of the outer medium, 

 whereas at the concentration of 0.125 per cent this is not the case. 

 Thus, the sugar is absorbed when the particles are present in the 

 sugar solution of a low concentration but excreted in that of a higher 

 concentration. Similar results are obtained with both glucose and 

 fructose, but not with lactose. This may account for the non-absor- 

 bability of the disaccharide. 



