114 S. C. PRESCOTT 



information on this subject. Search reveals relatively few papers, 

 however, in which the studies of the growth of bacteria in food 

 substances of high concentration have been reported, and even 

 fewer dealing with the development of yeasts and molds. A few 

 of these may be mentioned. 



Eschenhagen found that as the concentration of the substratum 

 increased fungi growing thereon modified their vegetative char- 

 acter, and especially developed swollen tips in the young hyphae. 



Rasciboski observed wall thickenings, giant cells, and multi- 

 plication of nuclei. 



Puriewitsch, in investigations on the growth of Aspergillus 

 pseudo-clavatus in concentrated sugar solutions found that the 

 walls became swollen, and the filaments developed the appear- 

 ance of a string of pearl beads. 



Klebs, in investigations on Aspergillus repens, found the limits 

 of concentration which the organisms could withstand were 95 

 per cent for grape sugar and 57 per cent for glycerin. Similar 

 results have been obtained by other investigators using fungi 

 as the organisms studied. Perhaps the most interesting and 

 illuminating of the investigations on this subject have been done 

 by our fellow members, the Kopeloffs, in their studies of deteri- 

 oration of cane sugar. They have found that in sugars contain- 

 ing as little as 1 per cent of water slight decomposition by fungi 

 could take place. Other investigations which need not be enum- 

 erated in detail here have shown that many fungi have the abil- 

 ity to develop in or upon substances almost devoid of water, and 

 our common experience with food substances and fabrics bears 

 witness on this point. 



With yeasts and bacteria, high concentration is apparently 

 much more inhibitive than with the thread fungi, although these 

 organisms too, can remain alive and sometimes increase slowly 

 in and upon substances containing small amounts of water. Ob- 

 viously, the character of the substance, its reaction and chemical 

 composition have much to do with the ability of the organisms 

 to remain viable. 



Laurent found that certain yeasts would grow in and ferment 

 60 per cent sucrose solution. I have personally observed sim- 

 ilar phenomena. 



