January 20, 1922] 



SCIENCE 



77 



use the plus ( + ) sign to denote degree of 

 acidity although he does use the minus ( — ) 

 sign for alkalinity. In a table which shows 

 the relationship of different degrees of reaction 

 to the number of bacteria developed (p. 393) 

 he presents under "reaction" the following 

 figures: 40, 35, 30, 25, 20, 15, 10, 5, 0, —5, 

 — 10, —15, —20, —25, adding, "Numbers 

 refer to cubic centimeters per liter of normal 

 acid or alkali necessary to change it to phe- 

 nolphthalein neutral point. Minus ( — ) means 

 an alkaline solution." The plus (+) sign was 

 apparently not used by Fuller, the figure itself 

 without any sign standing for acidity. While 

 the writer has not definitely ascertained when 

 and by whom the plus ( + ) sign was first used, 

 it is probable that it was first brought into 

 general use by the Report of the Committee of 

 Bacteriologists of the American Public Health 

 Association (2) in 1898. This committee, of 

 which Fuller was a member, made the follow- 

 ing recommendation (2, p. 75) : "Manner of 

 expressing the degree of reaction of culture 

 media : Since at the time the reaction is first 

 determined culture media are more often acid 

 than alkaline, it is proposed that acid media 

 be designated by the plus sign and alkaline 

 media by the minus sign, and that the degree 

 of acidity or alkalinity be noted in parts per 

 hundred" (writer's italics). "The bulk of 

 available evidence from both Europe and 

 America points to a reaction of + 1.5 as the 

 optimum degree of reaction for bacterial de- 

 velopment in inoculated culture media" (p. 76). 



It is quite evident that animal pathologists 

 and bacteriologists in general have substituted 

 for the methods proposed by Fuller those pro- 

 posed by the Committee of the American Pub- 

 lie Health Association of 1898, although they 

 usually cite or designate Fuller's scale, while 

 plant pathologists use Fuller's original recom- 

 mendations with the exception of adding the 

 plus ( + ) sign to indicate acidity. 



Since -flO.O, +15.0 in 1,000 c. c. of the 

 medium correspond to + 1.0, -f 1.5 respectively 

 in 100 c. c. of the medium it is evident that the 

 degree of acidity recommended for plant path- 

 ogens corresponds to the acidity recommended 

 for bacteria in general, and it is necessary to 

 know the author's interpretation of Fuller's 



scale when considering the degree of acidity 

 described or recommended. 



H. R. Rosen 

 Agricultural Experiment Station 

 University of Arkansas 



(1) Fuller, George W. On the proper reaction 

 of nutrient media for bacterial cultivation. 

 Jour. Amer. Pub. Health Asso., 20: 381-399. 

 1895. 



(2) Report of a Committee of Bacteriologists to 

 the Committee of the American Public Health 

 Association on the Pollution of Water Supplies. 

 Jour. Amer. Pub. Health Assc, 23: 56-100. 

 1898. 



(3) Park, W. H., and Williams, A. W. Patho- 

 genic microorganisms. Lee & Febiger, pub- 

 lishers, Philadelphia, 1920. 



(4) Smith, Erwin F. Bacteria in relation to 

 plant diseases. Vol. 1. Published by the Car- 

 negie Institution of Washington. 1905. 



(5) Smith, Erwin F. An introduction to bac- 

 terial diseases of plants. W. B. Saunders 

 Company, publishers, Philadelphia, 1920. 



THE AMERICAN CHEMICAL 

 SOCIETY 



(Continued) 



Division of Kubber Chemistry 

 W. W. Evans, chairman 

 Arnold H. Smith, secretary. 



Report of committees, executive, physical test- 

 ing, abstract, chemical analysis and accelerator. 



Mineral rubber: C. O. North. The purpose 

 of this paper is to bring out the desirable and 

 undesirable properties of M. E. in order that M. E. 

 makers will appreciate more fully how their 

 product is employed. Changes in stress strain 

 relations, hysteresis losses, permanent set, energy 

 of resilience and abrasion with increase in M. E. 

 ratio to rubber are shown. M. E. is essentially 

 :i plastic material. When a stock containing it is 

 stretched, the M. E. flows with the rubber. On 

 release the M. E. flows back with the rubber. 

 The principal evidence of its presence is a slow- 

 ing up or logging of the return. 



The Tetra-hyroxyphenyl derivative of rubber 

 and its tetra-methyl ether. Harry L. Fisher and 

 Harold Gray. The tetra-phenoxy derivative of 

 rubber described by Weber (ber. 33, 791) is 

 shown to be the tetra-hydroxyphenyl derivative 

 not only by the method of formation, and by its 

 solubility in aqueous NaOH, but especially by the 



