134 CLINICAL BACTERIOLOGY AND HEMATOLOGY 



Stain, is added and stirred well in, and the mixture covered with a 

 cover-glass. If there is an excess of fluid (so that the cover-glass 

 is floated up), it may be sucked up by means of a piece of blotting- 

 paper ; and if an oil-immersion lens is to be used, it will be 

 advantageous to seal the cover-glass down by means of melted 

 paraffin applied by a hot iron, so as to prevent it from being 

 lifted up by the suction of the oil between the lens and cover- 

 glass. If no positive results are found in the first specimen 

 examined, two or three more should be made, as the characteristic 

 organisms are often not distributed uniformly throughout the 

 vomit. Subsequently it may be necessary to prepare dried films 

 to determine whether the organisms stain by Gram. 



In catcinoma of the stomach the characteristic features are 

 (i) the presence of the Boas-Oppler bacillus, (2) the usual absence 

 of sarcinse, and (3) the absence of hydrochloric and presence of 

 lactic acid. In addition there may be blood, pus, and fragments 

 of tumour ; the latter are very rare and difficult to diagnose with 

 certainty. 



The Boas-Oppler bacillus, or B. geniculatus, is very characteristic 

 of carcinoma of the stomach, though it does not occur in every 

 case. It is very rare in other conditions ; I have seen it occa- 

 sionally in simple chronic gastritis, but here it is present in 

 numbers which are scanty as compared with the profusion in 

 which it occurs in malignant disease. It is a bacillus of large 

 size, and has a tendency to grow into long threads, which are 

 readily visible under a ^-inch lens (Plate IV., Fig. 5). In a 

 wet specimen these threads usually seem continuous, but on 

 examining a dried and stained specimen, they may be seen to be 

 composed of bacillary segments, much like the chains of the 

 anthrax bacillus. In a wet unstained specimen these threads are 

 very easily recognized, as they are highly refractile and may have 

 a slow, crawling motion, or may be non-motile : most usually 

 the latter. Another characteristic feature is the presence of an 

 obtuse angle in some portion of the length of many of the threads, 

 whence the name B. geniculatus is derived. The organism does 

 not form spores. It stains by Gram, and I have noted in several 

 cases the presence of a phenomenon which is very rare amongst 

 bacilli, that of longitudinal fission in a small number of the 

 chains, which thus come to form double rows of bacilli in close 

 1 ateral approximation. That this is not a mere effect of staining 

 is shown by the fact that occasionally the two bacilli at one end 



