550 



SCIENCE 



[N. S. Vol. XXXI. No. 797 



1. That at least 1 per cent, of all healthy school 

 children are carriers of morphologically typical 

 diphtheria bacilli (Wesbrook's A, C, D types). 



2. That such bacilli are communicable from one 

 to another and the condition is usually a transient 

 one. 



3. That the organisms are ordinarily of little or 

 no virulence. 



4. That while it is possible, by passing through 

 a susceptible individual, their virulence might be 

 raised to cause the disease, this is not a frequent 

 occurrence. 



5. That the disease diphtheria is kept alive in 

 a community rather by virulent organisms in 

 immune persons than by these non-virulent bacilli. 



6. That where virulent diphtheria bacilli are 

 present as shown by outbreaks of the disease, 

 cultural tests of all contacts and isolation of 

 those showing positive cultures is a duty owed 

 to the community. 



7. Where the disease does not exist, isolation of 

 carriers of probable non-vimlent bacilli is of no 

 proven benefit, and is a costly and laborious pro- 

 cedure entailing much unnecessary hardship on 

 innocent and probably harmless parties. 



8. The attempt to control diphtheria in a city 

 by a round of cultures from all school children at 

 the beginning of the school year does not seem 

 encouraging from this series of tests. 



9. The proposition to stamp diphtheria out of 

 a city by cultural tests of all the inhabitants and 

 isolation of all carriers is impossible from any 

 practical standpoint. 



The Virulence of Old Cultures and Subcultures 

 of B. mallei: B. L. Asms, M.D., Assistant 

 Director of the Bacteriological Laboratory of 

 the Boston Board of Health. 

 From work done at the Boston board of health 



laboratory the following conclusions are drawn: 



1. That in glycerine broth, B. mallei live and 

 retain their virulence for at least two months, 

 even when kept at body temperature. 



2. That a culture of B. mallei may be virulent 

 after growing on potato for at least a month. 



3. That some stains of B. mallei retain their 

 virulence through a great many subcultures on 

 artificial media. 



Eow shall the Value of Disinfectants he Deter- 

 mined? E. M. HorrGHTON, Detroit, Mich. 

 Some Observations on the Wassermann Reaction: 

 Laweence T. Clark, Detroit, Mich. 

 Departures from the principles upon which the 

 original Wassermann method for the serum diag- 

 nosis of syphilis is based are fraught with the 



dangers attending unreliable and, in many cases, 

 entirely erroneous results. In making the test a 

 thorough knowledge of the strength and keeping 

 qualities of the various factors entering into it is 

 very essential. Such facts, enumerated in the 

 conclusions, make it possible to diagnose a high 

 percentage of doubtful cases with a considerable 

 degree of accuracy. 



Conclusions. — The complement content of fresh 

 guinea-pig serum varies materially with different 

 pigs. 



More uniform and accurate results are obtained 

 when the guinea-pig serum is standardized to 

 known normal and syphilitic sera before doubtful 

 samples are tested. 



Hemolytic serum kept at uniform low tempera- 

 ture retains its activity for a relatively long time, 

 although it loses some of its original strength and 

 needs restandardizing from time to time. 



Suspensions of thoroughly washed red blood 

 corpuscles (ram) kept at 1.6° C. have been used 

 up to fourteen days after drawing with good 

 results. 



Samples of serum inactivated (56° C. one half 

 hour) and kept free from contamination, remain 

 unchanged for several days. This enables one to 

 store samples and run several at one operation. 



Practical tests made with properly standardized 

 reagents gave 95 per cent, and 93J per cent, accu- 

 rate results in known and doubtful cases, respect- 

 ively. 



Negative reactions were obtained after vigorous 

 specific treatment in eight cases which gave posi- 

 tive reactions before treatment. A future publica- 

 tion will deal with this phase more extensively. 



It would seem to be indicated by results from 

 the limited number of cases tested that the com- 

 plement fixation reaction, when carefully carried 

 out and thoroughly controlled, is a reliable means 

 for diagnosing the doubtful case. 



The Usefulness of Curves in, the Interpretation 

 of Biochemical Processes: Otto Eahn, Mich- 

 igan Agricultural College. 



If a curve of a biochemical process is plotted, 

 tasing as abscissa the time elapsed and as or- 

 dinate the total amounts of compounds produced, 

 the shape of this curve will in many instances 

 indicate the nature of the change taking place. 

 In a purely chemical or enzymatic change, the 

 active mass does not increase, and therefore the 

 rapidity of the process measured by the angle of 

 elevation of the curve does not increase. (Under 

 enzyme is understood a chemical compound, un- 

 able to multiply.) The curve changes with the 



