DIAGNOSIS 203 



PURPURA HEMORRHAGICA 



Some, probably not all cases of this disease, are of bacterial origin. Cultures 

 on blood-agar, ascitic fluid agar and blood serum should be made from the lesions, 

 venous blood and any enlarged glands that may be found. 



IMPETIGO CONTAGIOSA 



Impetigo contagiosa may be caused by pathogenic cocci. Observing the 

 necessary precautions to avoid contamination with saprophytic organisms 

 present upon the overlying crusts and contiguous skin, cultures should be made 

 from the lesions upon agar and blood serum. 



LUPUS 



Lupus, tuberculosis of the skin, is diagnosticated bacteriologically by ex- 

 amining scrapings from the lesions microscopically for tubercle bacilli, by ex- 

 cising a portion of the diseased skin and after proper treatment of it examining 

 microscopically both for tubercle bacilli and typical histological changes, by 

 injecting macerated scrapings from the lesions into guinea-pigs and rabbits and 

 by subjecting the patient to the tuberculin test. Not all these procedures are 

 necessary in every case. The multiplicity of methods of examination is de- 

 manded because one or several may fail in a particular case. 



FRAMB(ESIA 



Frambcesia or yaws is a non-veneral skin disease, similar to some of the super- 

 ficial manifestations of syphilis. It is caused by a spirochaete indistinguishable 

 from that of syphilis. The disease is diagnosticated by pinching up one of 

 the lesions, nicking the skin with a sharp knife (avoid producing hemorrhage), 

 and collecting the serum in a capillary tube. 



The serum is spread in a thin film on cover glasses, stained according to 

 the methods given for treponema pallidum, and examined. Yaws is differen- 

 tiated from syphilis microscopically by the larger number of spirochaete found 

 in every lesion of yaws than in syphilis. 



SYPHILIS 



In the first stage of syphilis a single, indurated ulcer develops at the site of 

 infection. More or less generalized macular and papular rashes and ulcers occur 

 from time to time during the second stage of the disease. 



The treponema may be found in the eruptions of the second and third stages 

 of the disease by following the technique as given for diagnosis of yaws. It is 

 better, however, to make the diagnosis by the Wassermann test. 



In the primary stage of the disease, the Wassermann test is frequently nega- 

 tive, especially early, bacteriological diagnosis must then be made by finding 

 treponema in the chancre or enlarged glands. After the chancre has been free 

 from germicides and disinfectants for 24 hours, and covered with a sterile dress- 

 ing, the dressing is removed, the ulcer washed with sterile salt solution, and 



