532 BACTERIOLOGY. 



or more revolutions per mintue; the threads are thrown 

 down. The " centrifuged" sediment will be found 

 to contain most of the bacteria present, epithelial cells, 

 and at times spermatozoa. Normal urine on being 

 " centrifuged" at this velocity will be found at times 

 slightly turbid at the bottom of the tube. This tur- 

 bidity will be found, on microscopical examination, to 

 consist of epithelial cells, a few leucocytes, and some 

 bacteria. 



Heiman looks upon the decolorization by Gram's 

 method as the only reliable criterion, so far as known, 

 for the gonococcus in discharges from the mucous mem- 

 branes, and it is of material help, also, in determining 

 whether a culture is or is not that of the gonococcus. 

 The careful examination of gonorrhoeal threads with 

 cover-glass by Gram's method is a very tedious affair, 

 as in every instance no less than three cover-glass prep- 

 arations should be looked over before the absence of 

 the gonococcus is proved. It would require many 

 hours upon each and every specimen, especially if the 

 gonococci are present in very small number, before a 

 reliable and conscientious opinion could be rendered. 

 If, after all, a negative opinion is ventured, we still 

 are under the necessity of proving that because the 

 threads which we fished out for the cover-glass exami- 

 nation were free from gonococci the remaining ones 

 were also. For this reason the culture medium is more 

 sensitive for bacteria than is the cover-glass, for we are 

 able to plant each and every thread of the sediment in 

 the centrifugal tube. Fiirbringer, in his work, men- 

 tions the fact that in certain cases the absence of the 

 gonococcus in many examinations of cover-glass prep- 

 arations is not a positive proof that the gonococcus is 



