202 BACTEKIOLOGY OF THE EYE 



secretion or membrane, spread out as evenly as possible ; these should 

 be stained by Gram's method. If after careful search we find no 

 bacilli of the diphtheria group, then the case is not one of diphtheria. 

 Sufficient material 1 should always be taken, and the case must not 

 have been treated. 



If the rods described above are seen, we must examine them care- 

 fully with regard to their form and length (cf. p. 190). If Neisser's 

 polar staining is found to be positive and typical, then toxic diph- 

 theria bacilli are probably present. When the number of the bacilli 

 and other organisms (especially titaphylococci and Streptococci] present 

 is very great, we should rub some of the material on to three tubes 

 or Petri dishes. I like to use as agar as I and II serum, so that 

 isolated serum colonies will certainly be obtained. When the cultures 

 are made before midday, then in the evening, in ten to twelve hours, the 

 colonies can be seen with the loupe, and from characteristic colonies 

 smear preparations can be made, some stained with Neisser's polar 

 stain and others with Gram. A positive result with Neisser's stain 

 makes the diagnosis still more likely. 



If isolated colonies occur on the original tube, then make a bouillon 

 culture, into which the greatest possible number of colonies which 

 can be macroscopically and microscopically determined to be charac- 

 teristic are introduced into the same bouillon tube (10 c.cm.). I do 

 this because we can very well have toxic and non-toxic bacilli occur- 

 ring together (Schirmer). If we take only one colony and obtain 

 no result, it cannot be concluded that all the other colonies would 

 have been the same. On the other hand, by the use of ten to 

 twenty colonies we are practically certain. Naturally we most care- 

 fully examine such a bouillon culture in twenty-four hours in hanging- 

 drop and in stained smear, to make sure that only Bacteria of the 

 diphtheria group are contained in it before using it for inoculation. 

 We further test the bouillon for acidity. 



If it be a pure culture, I inject 2 c.cm. of the culture subcu- 

 taneously into a guinea-pig. If death occurs in two to six days with 

 the characteristic symptoms, then we have definitely a toxic organism 

 present. The site of the injection is doughy, sometimes covered with 

 a white material, and a section of the surrounding tissue is juicy and 

 haemorrhagic ; there is hypereemia of the adrenals, exudate in the pleura, 



1 Dutoit recommends that, on getting a negative result, material should be again taken 

 from another spot. In one case the result at first was negative, but in the debris of a 

 corneal ulcer virulent diphtheria bacilli were found. I always make several preparations 

 from different places. Valude makes the same recommendation (Ann. d'Oculiste, 1894, 

 cxi. 290). 



