266 



SCIENCE 



[N. 8. Vol. LIII. No. 1368 



crose in the ^presence of dextrose ,and of dextrose in 

 the presence of sucrose, and finally of dextrose in 

 the presence of levulose were measured. The re- 

 sults of this investigation have shown the maxi- 

 mum concentration which invert sugar may have 

 without depositing crystals of dextrose, and sim- 

 ilarly the maximum concentration which a mixture 

 of sucrose and invert sugar may have without de- 

 positing cither sucrose or dextrose. The syrup 

 which contains 29 per cent, of sucrose and 52 per 

 cent, of invert sugar, or a content with respect to 

 total sugar of 81 per cent., has this maximu m 

 concentration. In general, it is practicahle to in- 

 crease this concentration even to a slight supersat- 

 uration without danger. Such a solution is sufi- 

 oiently dense for a good syrup and resists the 

 growth of microorganisms. A number of methods 

 of inverting sugar have been devised. We add the 

 suggestion that the partial inversion can he accom- 

 plished hy the aid of an extremely dilute hydro- 

 chloric acid and subsequent neutralization with 

 sodium carbonate. The net result is the addition 

 of a minute quantity of common salt. Data are 

 provided for controlling the method. During the 

 investigation, the densities of invert sugar solu- 

 tions, the contraction of volume accompanying in- 

 version, and the change of viscosity were deter- 

 mined. 



Some characteristics of imported cane sugairs: 

 C. A. Browne. The general trend in the manu- 

 facture of raw cane sugar during the past decade 

 is shown to be towards the production of 96 test 

 sugar, which during the past 5 years has made up 

 about 75 per cent, of the total importations. This 

 percentage could be increased considerably if care 

 were taken to manufacture a drier sugar that 

 would not deteriorate. Some of the chemical, 

 .physical, mycological and entomological character- 

 istics of the different grades of imported raw cane 

 sugars are discussed. During the past year, con- 

 siderable plantation white sugar, testing between 

 98 and 100, has been imported for direct consump- 

 tion. Some of this sugar is of very good quality 

 and if care were tahen always to make a clean 

 white sugar of uniform character plantation white 

 sugar might find a considerable demand even 

 among the more discriminating class of users. 



American progress in iacteriological sugars: 

 Eduond H. Eitel. The history of the rare sugars 

 virtually commences with 1883. The sugars had 

 become essential in bacteriology when in 1914 the 

 German supply was cut off. The U. S. govern- 

 ment found its work critically handicapped. Ap- 



peals of a patriotic nature established a rare 

 sugar production in America. Erom the labora- 

 tory stage to the commercial represents a far 

 greater achievement than is apparent. The fol- 

 lowing sugars are now manufactured commer- 

 cially: 1-arabinose, dulcitol, d-galactose, d-glucose, 

 glycogen, inositol, inulin, invert sugar, lactose, 

 d-levulose from invert sugar, d-levulose from 

 inulin, levulose, syrupy, maltose, d-mannitol, 

 d^mannose, melezitose, rafSnose, rhamnose, sorbitol, 

 sucrose, trehalose and d-kylose. A greater achieve- 

 ment than this list, however, is the surpassing of 

 the old standards of Kahlbaum and the discredit- 

 ing of another German superman theory. The 

 polariscope with variable sensibility, a device of 

 American invention, and the growing knowledge of 

 how accurately bacteria can detect minute Impuri- 

 ties has stimulated the new standard. The use of 

 the rare sugars in America is being extended to 

 physic-chemistry, chemical analysis, diet, intra- 

 venous injection, plant pathology, medicine and 

 even to experimental explosives, as weU as to ad- 

 vances in bacteriology. A specific example of the 

 importance of the sugars to national health and 

 epidemiology is the differentiation possible by 

 their means of the paratyphoid, meat poisoning and 

 hog cholera bacUli and the resulting possible 

 knowledge of the source of an epidemic. The so- 

 lution of the problem of the sugars calls for both 

 the chemist and bacteriologist in combination, and 

 in the answer light will be thrown upon morph- 

 ism and bacteria, configuration of sugars, the 

 asymmetric carbon atom, theory of life and evolu- 

 tion. 



Eesults of sugar cane experiments in St. Croix: 

 LoNGFiELD Smith. 



Use of Tcieselguhr in the clarification of cane 

 juice: H. S. Paine and C. E. Walton, Jr. Ee- 

 sults are reported of a comparative study of vari- 

 ous types of kieselguhr, or diatomaceous earth, 

 for the purpose of correlating physical properties 

 and clarifying efSciency as a possible means of 

 determining relative market values. The investi- 

 gation of clarifying efficiency has led to a quanti- 

 tative study of the colloids removed from cane 

 juice by different methods of clarification. These 

 experiments included a microscopic examination 

 of the various kieselguhrs, tests of comparativa 

 rate of filtration, sedimentation, fineness by siev- 

 ing solubility in dilute acids and alkali, and th« 

 quantitative determination by dialysis of the col- 

 loids present in the juice before and after clarifi- 



