416 EXPERIMENT STATION RECORD. [Vol.41 



fumes evolved escape freely, and within certain limits the higher the temperature 

 of final heating the greater the decolorizing effect of the resulting carhon. 



In the second investigation, various plant materials high in ash were used 

 for the preparation of decolorizing carbons with a view to the discovery of some 

 cheap raw material for the production of effective carbon on a commercial 

 scale. Of the materials examined, two were thouglit to be promising for com- 

 •mercial use — rice hulls and Pacific coast kelp. The most efficient methods for 

 preparing these are described in detail. The former under the process finally 

 adopted yields a carbon of a decolorizing power of 145 in percentage of Norit, 

 and the latter of over 300. 



The by-products and similar materials employed in the last part of the in- 

 vestigation included bagasse, filter press cake, impregnated molasses carbon, and 

 a mixture of a black vegetable mold and finely divided calcium carbonate which 

 occur in consecutive strata in some districts in Porto Ilico. While not possessing 

 the high efiiciency of the carbon noted above, some of these materials would 

 seem to offer cheaper sources of carbons greatly suiter ior to bone black in 

 decolorizing power. 



The deterioration of cane sugar by fungi, N. and L. Kopeloff {Louisiana 

 Stas. Bill. 166 (1919), pp. 3-72, figs. 3).— This bulletin contains a survey of the 

 fungus flora of the different types of cane sugar and the results of an investi- 

 gation of the deterioration of cane sugar by fungi in pure culture, and of the 

 presence of these organisms in the different stages of sugar manufacture. 



Various media and a wide range of cane sugars were used for the isolation 

 of the fungi. Czapek's agar was found to have the greatest relative efficiency 

 of all the media studied for isolating a variety of fungi. A modification by 

 the authors of this medium resulted in a more rapid colony development. This 

 modification consisted in increasing the sucrose content from 30 to 50 gm. 

 per liter and substituting 5 gra. of peptone and 1 gm. of ammonium nitrate 

 for 2 gm. of sodium nitrate in the original formula. 



The fungi isolated belonged chiefly to the Aspergilli and Penicillia. Asper- 

 ffillus nigcr and a blue Aspergillus occurred in practically all samples. The 

 latter, which appeared with the greatest frequency in all sugars, also had 

 the greatest deteriorative power. Sterilized sugars inoculated with pure cul- 

 tui'es of fungi deteriorated rapidly when the moisture content was appre- 

 ciable, but only very slightly, if at all, when the moisture content was reduced 

 to a minimum. Slight evidence of deterioration occurred in plantation granu- 

 lated sugar with a factor of safety of 0.1 and. in Cuban raw sugar with a 

 factor of 0.2, which would indicate that the factor of safety for sugars in- 

 fected with fungi is lower than generally supposed. The fungi spores were 

 found to contain invertase and consequently to be responsible for the inversion 

 of sucrose. 



A daily bacteriological and niycological examination of each stage in the 

 process of sugar manufacture showed that fungi and bacteria were found in 

 greatest numbers in tlie raw juice. The clarification process served to sterilize 

 the juice but i-einfection took place in the massecuite in and about the cen- 

 trifugal. 



As practical deductions from this study the authors emphasize the importance 

 (1) of reducing the moisture content of the sugar as much as possible and 

 avoiding the subsequent access of moisture, and (2) of using every precaution 

 to prevent reinfection of the massecuite after it leaves the vacuum pans. Sug- 

 gestions are given for improvements in factory conditions and for proper 

 methods for tlie handling and storage of the sugar after it leaves the cen- 

 trifugal. 



A list of 46 references to the literature is included. 



