2 go 



SPECIFIC MICRO-ORGANISMS 



of plasma containing leukocytes, epithelial cells and bacteria, 

 and this coagulates on the mucous surface. The epithelium 

 underneath also undergoes necrosis in moderately severe cases 

 and is firmly attached to the exudate by the fibrin threads. In 

 severer forms there is an escape of blood into the exudate giving 

 it a dark color. The local lesion is largely due 

 to soluble toxin formed by the bacilli. The gen- 

 eral disturbance is, as a rule, due solely to the 

 absorbed toxin. The bacilli remain at the site of 

 the lesion and do not appear in the blood or in- 

 ternal organs in any appreciable numbers. They 

 are occasionally found in the spleen or kidney 

 of fatal cases, but not more frequently than the 

 streptococcus is found in these organs in appar- 

 ently uncomplicated fatal cases of diphtheria. 



The local lesion in the throat may be simu- 

 lated very closely by inflammation due to strep- 

 tococci, but the general manifestations are not 

 duplicated in such conditions. Mixed infection 

 Swab with diphtheria bacilli and virulent streptococci 

 and culture-tube mav present a clinical picture of great severity. 



used in the diag- J - J 



nosis of diphthe- Bacteriological examination is often a great help 

 oT'cotton on d fhe m diagnosis even to the expert clinician, and is 

 wire shown is quite generally employed. 



much too bulky. . 7 . 7 ~ . . / r .. n i T 



Bacteriological Diagnosis of Diphtheria. In 

 many large cities the bacteriological diagnosis of diphtheria is un- 

 dertaken by boards of health. The methods used differ somewhat 

 in detail, but are similar in the main, and are based upon the pro- 

 cedure devised by Biggs and Park for the Board of Health of New 

 York City. Two tubes are furnished in a box. The tubes are like 

 ordinary test-tubes, about three inches in length, rather heavy and 

 without a flange. Both are plugged with cotton. One contains 

 slanted and sterilized Loffler's blood-serum mixture (Fig. 122); 

 the other contains a steel rod, around the lower end of which a 

 pledget of absorbent cotton has been wound. These tubes con- 



