374 ABSTRACTS 



Study of the Blood with a New Stain. B. Lemchen. (Medical Record, 



1916, 89, 607-608.) 



The stain consists of a saturated solution of benzidine in absolute 

 alcohol. Blood smears are made on slides and placed in the stain 

 for one-half minute. The slide is then placed in hydrogen peroxide 

 for one-half minute, washed in water and dried on filter paper. 



In studying blood stained in this way, it is assumed that cells and 

 tissues of similar composition react in the same way, as staining is a 

 chemical reaction. Red cells, nucleated red cells including both cell 

 and nucleus, and fibrin stain blue; white cells and blood platelets do 

 not take the stain. From this it may be concluded that red cells and 

 white cells are of different origin, that platelets do not have their origin 

 in the nucleus of the red cells, and that fibrin has the same composition 

 as the red cells. 



These conclusions may throw some light on the processes of coagula- 

 tion of the blood and certain phases of hemophilia leading to pernicious 

 anemia. According to this line of reasoning, it may be possible that 

 the origin of agglutinins in typhoid is in the red blood cells. — M. W. C. 



A Method of Demonstrating Bacteria in Urine by Means of the Centrifuge. 



With Some Observations on the Relative Value of Examinations by 



Culture or Stained Sediment. E. G. Crabtree. (Surg., Gyn., and 



Obstet., 1916, 22, 221-224.) 



The method consists in slow centrifugation to remove the heavier 

 sediment, then rapid centrifugation until the urine is clear in order 

 to throw the bacteria out of suspension. C. calls attention to the 

 danger of mistaking smegma for tubercle bacilli, guinea pig inoculation 

 being the final test for infection with tubercle bacilli. The author 

 thinks inconsistent results are obtained because of lack of uniformity 

 in culture media, etc., while organisms such as B. coli may overgrow 

 the others. Microscopical examination assists in determining the 

 degree of infection, and predominating organisms, and if there is a 

 mixed infection helps to determine cultural method to be used. 



Comment. The author does not mention the use of Petroff 's method 

 for direct culturing of tubercle bacilli or the necessity of using the 

 antiformin method where T, B. is suspected and other infection already 

 exists.— C. P. B. 



A Rapid Method of Counting Living Bacteria in Milk and Other Richly 



Seeded Materials. W. D. Frost. (Journ. A. M. A., 1916, 66, 889- 



890.) 



A detailed account of the procedure is given. The method is essen- 

 tially as follows: 



"One-twentieth cubic centimeter of milk is mixed with standard nutri- 

 ent agar and spread over a definite area of a sterile glass slide. When the 

 agar is hard, this little plate culture is put in the incubator for about six 

 hours under conditions which prevent evaporation. It is then dried, 

 given a preliminary treatment to prevent the agar from firmly binding 



