122 



Scientific Proceedings (112). 



organisms in the capsule are to some extent protected against 

 phagocytes, and other protective factors. The capsules are usu- 

 ally surrounded by fibrin and strands of connective tissue, and 

 lie in a membrane of tissue that has grown about them. 



Incidentally, it has been noticed that in the case where the 

 capsule had remained in place four months, the organisms were, 

 at the end of this time, culturally and morphologically identical 

 with the ones that had been put in, which furnishes some evidence, 

 at least, against the mutations of streptococci in the animal body 

 advocated by Rosenau. 



58 (1640) 



The effect of temperature and of hydrogen ion concentration upon 

 the rate of destruction of antiscorbutic vitamine. 



By V. K. LAMER, H. L. CAMPBELL, and H. C SHERMAN. 



[From Columbia University, Department of Chemistry, 

 New York City.} 



Experiments were made upon 300 gram guinea pigs fed a new 

 basal diet designed to furnish practically optimum amounts of all 

 nutrients except the antiscorbutic vitamine. The latter was 

 furnished exclusively in the form of filtered canned tomato juice. 

 Relative amounts of this vitamin in the treated and untreated 

 portions of this juice were measured by determining the amounts 

 necessary to prevent scurvy or by a quantitative rating of the 

 severity of the scurvy produced. The technique and the probable 

 degree of precision of the results will be discussed in a later paper. 



In the case of tomato juice of natural acidity, P H 4.2, it was 

 found that boiling for one hour destroyed practically 50 per cent., 

 and for four hours practically 70 per cent, of the antiscorbutic 

 vitamine present. The time curve of the destructive process is 

 therefore much flatter than that of a unimolecular reaction. The 

 latter finding applies also to similar heating experiments at 6o° 

 and at 8o°. In such experiments at 6o° to ioo°, the temperature 

 coefficients are relatively low (Qi 0 = 1.1 to 1.3). 



In experiments in which the natural acidity was first neutral- 

 ized in whole or in part, the juice then boiled for one hour and 



