196 BACTERIOLOGY OF THE EYE 



On gelatine at 18 C. growth almost never occurs ; at the very most, we may find 

 here and there the scantiest traces along the needle track. 



There is no general pathogenicity for guinea-pigs, even when large doses are 

 injected subcutaneously. A few authors (Spronk, C. Frankel, and Pes) have obtained 

 transient swelling at the site of inoculation. C. Frankel states that many of the 

 animals died later from marasmus. In conjunction with many of my students 

 (cf. papers by Heinersdorff, Bietti, Plaut, and Zelewski), I have performed many 

 inoculations without being convinced that such was the case, unless enormous 

 doses were employed. These changes and the local reaction to inoculation in the 

 eye have nothing to do with diphtheria toxic action. 



There can be no doubt that the two varieties do exist, for the description first 

 given by Hofmann, and since then found applicable to the great majority of the 

 avirulent ' pseudo-diphtheria ' organisms which occur in the throat, is not applicable 

 to the majority of the conjunctival xerose bacilli. 



That the great majority if not, indeed, all of these organisms show marked 

 differences in their power of growth when they come from the two chief sites where 

 they exist (the eye when they grow sparsely, and the throat when they grow freely), 

 appears worthy of note. 



It is still uncertain whether the special nutritive conditions present in particular 

 persons can develop these differences, or whether one variety flourishes better than 

 the other in some individuals. According to the researches of Veillon, both forms 

 are to be found in the genital tracts in women. 



These differences are very clearly pointed out in the recent works by Schwoner, 

 Gromakowski, Lewandowski, and Tertsch. Quite in accord with my own observa- 

 tions, they divide the diphtheria organisms into two groups : (a) growing sparsely ; 

 (6) growing profusely. Tertsch agrees with Schwoner in calling the profuse group 

 Hofmann's bacilli ; the sparsely growing group, on the other hand, seeing that they 

 more nearly resemble in their cultures the true diphtheria bacilli, they term 

 ' pseudo-diphtheria ' bacilli. I cannot entirely support this idea, as the custom is to 

 use this last name for the Hofmann bacillus, as, for example, in Lehmann-Neumann 

 and other text-books of bacteriology. It will, perhaps, be sufficient if we contrast 

 the profuse (Hofmann's) with the sparse type. 



The exact differentiation of the varieties which we have described, as also that of 

 the pseudo from the true diphtheria bacilli, is often complicated by the occurrence of 

 variable strains. Some of these strains resemble each other in one particular or 

 another, and others seem to conform to the type of the true diphtheria bacillus. 

 Further subdivision according to such criteria would be quite artificial, and 

 Lehmann and Neumann are correct in stating that the subdivision into three 

 classes of pseudo-diphtheria bacillus, as, e.g., by Gromakowski, cannot be carried 

 through. 



A classification has been attempted on the basis of agglutination (Nicolas, 

 Nicolle, Landsteiner, Lesieur, Bruno, Lubowski, C. Frankel, and Schabad). With 

 such a non-motile organism, with a tendency to the formation of a scum in the 

 culture, the determination of agglutination would be difficult, and the results obtained 

 did not agree. 



Nicolas, using the serum of convalescent diphtheria patients, succeeded in 

 agglutinating virulent strains in a 1 in 10 dilution, and avirulent in 1 in 20 ; but he 

 also found true virulent strains which were not thus agglutinated. 



Bruno obtained agglutination with the serum of diphtheritic patients up to 

 1 in 400, but normal serum had the same result up to 1 in 30. With a serum 

 obtained by the action of an atoxic diphtheria strain Lubowski was able to 

 agglutinate twenty-three virulent and two avirulent diphtheria strains (dilution 

 1 in 40 and 1 in 80), while pseudo-diphtheria strains did not react. Lesieur, on the 



