The Fermentation of Galactose by Yeast and Yeast-juice. 645 



become dried, if they are wetted again with water." It also differs from 

 many Mycetozoa in growing in strong suuhght.* 



It would be of interest to examine in this way the rudimentary organisms 

 which at present occupy an undefined position between the two great 

 divisions of Uving matter. If protoplasm is identically the same in animal 

 and vegetable cells the principle of life for each must be the power of 

 determining its activity so that as a result the charge of one becomes negative 

 and the other positive. It is also possible that the protoplasm itself may 

 not be the same, and that the characteristic electrical charge is obtained not 

 by separation within the cell but by selective absorption from without, so 

 that the protoplasmic cell-content cannot be regarded as quite the same in 

 the two cases. 



In conclusion I wish to express my indebtedness to my colleague, 

 Prof. H. J. Hutchens, for most useful advice. 



The Fermentation of Galactose by Yeast and Yeast-juice. [Pre- 

 liminary Communication.) 

 By Arthur Harden, F.E.S., and Roland V. Norris. 



(Received July 18, 1910.) 



(From the Biochemical Laboratory of the Lister Institute.) 



Numerous investigators have shown that many species of yeast which 

 ordinarily do not ferment galactose, readily acquire that property when 

 cultivated in a medium containing that sugar. 



The present communication briefly describes experiments which have been 

 made with living yeast in this way, and with the juice obtained from this 

 yeast. Experiments are also proceeding with yeast " killed " by acetone and 

 other reagents (zymin), and it is hoped when these are complete to give 

 a more detailed account of the whole investigation in a future paper. 



Pure cultures of S. Carlsberg I have been used throughout these experi- 

 ments. The medium employed for " training " the yeast consisted of yeast 

 water to which was added 20 per cent, of hydrolysed lactose and 0-15 per cent. 



of K2HPO4. 



* Loc. ctt., p. 48. 



3 B 2 



