ABSTRACTS 111 



Food value. Bacteriology bears no direct relation to food value. 

 It might bear an indirect one if high term content was accompanied 

 by a lowering of food value. In commercial milk this reduction is not 

 appreciable, except as induced acidity interferes with certain uses of 

 milk. 



Freedom from disease germs. Bacteriology has everything to do 

 with this feature, but practically we have no method of determining 

 the presence of such germs and protection must be sought through 

 omnibus methods such as pasteurization. Pasteurization control is 

 mainly through time and temperature. 



Cleanliness. Added uncleanliness is probably best measured by 

 bacteriological counts if they are made at the time of infection. How- 

 ever, as soon as the elements of time and temperature enter, such counts 

 no longer indicate the character or extent of contamination. 



Conclusion. Quantitative bacterial standards of 1,000,000 or any 

 similar number do not throw any hght upon two of the three elements 

 which are important in judging a milk supply, and unless the age and 

 temperature history of the milk is known they do not give any important 

 information regarding the third element. 



Purification of Sewage by Aeration in the Presence of Activated Sludge. 



Edward Bartow. 



By blowing air into sewage then allowing the suspended matter to 

 settle and decanting the supernatant Hquid, adding fresh sewage and 

 repeating the operation, there is accumulated sludge which has the 

 property of purifying sewage, in the presence of air in from four to 

 five hours. The sludge obtained contains more nitrogen than sludge 

 obtained by any other method of sewage purification. It has been 

 shown by analyses and by experiments with growing plants that it is 

 valuable as a fertilizer. By the process a bacterial reduction of 95 to 

 99 per cent is effected. The cost of the process depends upon the cost 

 of producing air. It has been estimated that it will be the most effec- 

 tive and most economical method of sewage purification. This will 

 be especially true if the sludge can be readily recovered and disposed 

 of for use as a fertihzer. Plants of considerable size have been con- 

 structed at Milwaukee, Cleveland and Champaign and the process 

 will be given a thorough trial. 



Diphtheria Diagnosis by means of Blood Serum containing Potassium 



Tellurate. Will Shimer. 



The medium for diphtheria cultures devised by Conradi and Troch 

 has not been generally adopted apparently for two reasons; first, the 

 tellurite salt instead of the tellurate salts has been used by most workers, 

 second, the Conradi medium was first recommended as a color differ- 

 entiating medium as well as an inhibiting. The color differentiation 

 medium is now believed to be of Httle help. 



The Bacteriological Laboratory of the Indiana State Board of 



