and Laboratory Methods. 1687 



The diplococci of pneumonia will appear well stained, with the capsule also 

 stained. Most other bacteria will be decolorized. 



V • -^ ^ 









H^"-L> 



Fig. V. Pneumococcus from the blood. Case fatal. Fig. VI. Bacillus typhosis, culture. Methyl-violet 



Acetic acid method of staining. Magnified 1200 diani- stain. IMagnified 1200 diameters ; j'^ oil immersion 



eters ; y'^ oil immersion objective, Zeiss projection objective, Zeiss projection ocular No. 4. 

 ocular No. 4. 



BACILLUS TYPHOSIS. 



The determination of typhoid bacilli by direct microscopical examination of 

 the faeces is not practical. Morphologically, they are so similar to the Bacillus 

 coli communis that special bacteriological methods are necessary. Simple 

 methods only are given here, which if carefully followed will yield satisfactory 

 results. For more complete information the reader is referred to standard works 

 on bacteriology. 



Widal's reaction with dried blood offers the most practical assistance. The 

 finger or lobe of the ear is carefully cleaned and dried. A large drop of blood 

 from a needle prick should be collected on a clean and sterilized cover-glass or 

 piece of mica. Either may be cleaned by washing in soap and water, thoroughly 

 rinsed in clear water, and steriUzed by passing through the flame of an alcohol 

 or Bunsen burner several times with first one side and then the other uppermost. 

 The drop of blood should be allowed to dry without heat, and then sent to the 

 state health laboratory, or to the laboratory of some bacteriologist, for the com- 

 pletion of the test, as follows : With the platinum loop, a small drop of sterile 

 bouillon is gently mixed with the dried blood until a dark brown fluid results. 

 This is mixed on a cover-glass with a drop of pure bouillon culture of typhoid 

 fever bacilli, and inverted over the concavity of a hollow ground slip. A little 

 vaseline or oil is smeared around the edge of the cover-glass to prevent evapora- 

 tion. It is now ready for examination under the microscope. At first the 

 bacilli will be found actively motile, but if the blood is from a typhoid fever 

 patient the motility will become gradually lessened and will almost entirely cease ; 

 at the same time the bacilli will become agglutinated in clumps. The reaction, 

 if positive, should occur within half an hour. 



It is hardly practical for the busy practitioner to have a suitable culture of 

 typhoid bacilli ready for this test, but the establishment of state and municipal 

 health laboratories in nearly every large city and state in the Union renders it 



