208 MEDICAL BACTERIOLOGY 



and surrounding parts and cover with a sterile dressing, without any germicide 

 or antiseptic; after this dressing has been on for 12 to 24 hours remove it and 

 obtain some serum, also scrapings from the floor of the ulcer; examine these 

 specimens unstained, microscopically, using the dark-field microscope; if trepo- 

 nema pallidum is observed the diagnosis is established; if not observed, proceed 

 as follows: obtain serum and scrapings from the ulcer, spread on slides or cover 

 glasses, dry without heating and stain some with methylene blue, others by 

 Gram's method and others by Giemsa's method for treponema pallidum; if 

 desired, cultures may be made on blood-agar, ascitic agar and inoculation into a 

 rabbit's testicle. 



The treponema pallidum is present in chancres, either in pure culture or 

 together with other organisms. 



Chancre and chancroid may exist together, in which case the organisms of 

 both conditions will be found. 



Ducrey's bacillus (bacillus of soft sore) is considered the specific cause of 

 chancroid. Other organisms are usually found with it staphylococci, gono- 

 cocci or micrococcus tetragenus. 



Ducrey's bacillus is a short rod or oval, 0.5 fj, by 2.0 /*, has round ends, is non- 

 motile, is arranged singly and in chains, occurs within pus cells and outside of 

 them, stains readily with all the usual anilin dyes and is Gram negative. It does 

 not stain uniformly, the poles stain deep, the intervening portion faintly or not 

 at all. 



Ducrey's bacillus does not grow on ordinary media. On blood-agar in- 

 cubated aerobically at 3iC., round, raised, pin-head-sized, opaque, grayish 

 colonies develop in 24 to 48 hours. 



ACUTE URETHRITIS AND VAG1NITIS 



Acute urethritis or vaginitis may be caused by staphylococci or gonococci, 

 rarely by other organisms. Microscopic examination of smears made from the 

 discharge and stained by methylene blue and by Gram's method will establish 

 the diagnosis in nearly all cases. 



CHRONIC URETHRITIS AND VAGINITIS 



Chronic urethritis and vaginitis may be due to a single organism, usually 

 several are present. When due to a single organism it may be impossible to 

 find it except following an unusual irritation or hypersecretion such as may be 

 produced by drinking beer, massage of the prostate or sexual excitement. If 

 spreads and cultures fail to show the offending organism, they should be again 

 made after instituting irritation or hypersecretion. Cultures are made by 

 picking up some of the discharge and planting it on the surface of Loeffler's 

 blood-serum medium and on neutral ascitic agar. Tubes containing no free 

 moisture must be used and it is best to plant several so that some may be incu- 

 bated with reduced oxygen tension and others aerobically at 37C. 



When chronic urethritis or vaginitis is due to several organisms there is usu- 

 ally sufficient discharge to permit of diagnosis by microscopic examination of 



