506 TH. THJ0TTA AND ODD KINCK EIDE 



wet colonies, and the bacilli of this group are small bacilli without 

 any motility and also lack agglutinability. These facts rendered 

 it necessary to examine our strain with a capsule dye. It was a 

 fairly easy task to demonstrate great masses of mucus in slides, 

 prepared from our cultures. The bacilli were not surrounded 

 by small distinct capsules as is the case in pneumococci. The 

 capsules were very thick, surrounding one, two or many bacilli 

 in a common cover of mucus. Between the heaps of bacilli there 

 were great masses of mucus, arranged as a homogeneous inter- 

 cellular substance. This marked formation of mucus might also 

 be demonstrated directly in the cultures, as these were quite 

 sticky and often in agarslope cultures produced mucus that flowed 

 down into the bottom of the tube. 



At this point in our investigation we happened to come across 

 a strain of Bad. pneumoniae in a case of pneumonia in a guinea- 

 pig. We could now compare the two strains, and we have the 

 greatest difficulty in telling which of the strains was the para- 

 typhoid and which the pneumonia bacillus seen on the plates. 



We consequently consider it proved that our atypical strain has 

 obtained the faculty of forming capsules or rather of producing 

 great masses of mucus. This explains very well the peculiar 

 growth, the small bacilli, the slight motility and the slow agglu- 

 tinability. The strain is of a special interest as it has been 

 watched during its growth in typical manner in the urogenital 

 tract of the patient and has been seen to develop into the capsule 

 producing variety. 



It looks as if our strain must be considered a true transmutation 

 of the paratyphoid bacillus. The strain developed the new char- 

 acter quite suddenly and has kept it unaltered for more than f 

 year. It thus appears to be very constant, but it would be of 

 interest to show that it kept unaltered even if the strain was 

 cultivated rapidly for several generations from the one directly 

 to the next without being allowed to stand over in the laboratory 

 between the cultures. We consequently secured a well isolated 

 colony and spread it on agar plates. After twenty-four hours of 

 growth a new colony was taken out, spread again and this was 

 done daily for three weeks. The first few cultures showed a 



