670 BACTERIUM 



be subcultured, and obtained pure. The growth of these non-capsulated bacilli 

 was no longer mucoid, but resembled the growth of Bad. coli. Regression to the 

 mucoid type might occur — often suddenly. As well as this non-mucoid type, 

 Toenniessen (1914) later observed three other variants. The mucoid, capsulated 

 type may be regarded as the smooth form, and the non-mucoid, non-capsidated 

 type as the rough form of Friedlander's bacillus (Julianelle 19266). Dissociation 

 may take other forms. Thus, according to our own observations, secondary 

 colonies may appear in the substance or on the surface of the original colonies ; 

 or there may develop a jelly-like, translucent peripheral fringe showing slight 

 radial striation ; or sometimes the whole colony may dry up and wither away, 

 leaving an effuse, transparent layer looking like ground glass — aptly called by 

 ColUns (1924) " suicide " colonies. Beham (1912), Hadley (1927), and Goslings 

 (1935) have recorded similar observations. 



Resistance and Metabolism. — The organisms are killed by moist heat at 55° C. 

 in half an hour. They may survive drying for months (Loewenberg 1894). If 

 kept at room temperature, cultures remain viable as a rule for weeks or months. 

 They are aerobic ; growth under strictly anaerobic conditions is very poor. There 

 is no haemolysis of horse's or sheep's red cells. The optimum temperature for 

 growth is 37° C, the limits are 12° and 43° C. Some strains form a slightly brownish 

 pigment, most easily produced by growth on potato. 



Biochemical Reactions. — The fermentation of sugars by members of this group is subject 

 to considerable variation (Clairmont 1902, Perkins 1904, 1907, Edwards 1905, Page 1912, 

 Fitzgerald 1914, Coulter 1917, Small and Julianelle 1923, Bamforth 1928, Edwards 1928, 

 1929, Julianelle 1930, 1935, Elbert and Guerkess 1930, Hay 1932, Wallace, Cahn and 

 Thomas 1933, Morris and Julianelle 1934, Kliewe and Hsii 1935, Wilson et al. 1935, Goslings 

 1934, Osterman and Rettger 1941). Many strains produce acid and gas in glucose, maltose, 

 mannitol, lactose, sucrose, and saUcin. Several, however, do not attack lactose, and others 

 either do not ferment sucrose, or ferment it late. Gas may be formed rapidly or not for 

 several days ; some strains do not form gas. Occasionally no sugars are fermented, but 

 this lack of fermentative abiUty is uncommon except in strains that have been subcultured 

 for a long time in the laboratory. In Utmus mUk also the reaction of different strains 

 varies. Generally acid and clot are formed, but many strains do not produce sufficient 

 acid to precipitate the caseinogen, while some strains produce no change at aU. The litmus 

 is occasionally decolorized. 



There is fairly general agreement that biochemical reactions do not afford an adequate 

 basis for classification, since most workers have been unable to discover any constant 

 relationship between the biochemical activities of a given strain and its source of origin 

 or antigenic structure. Goslings (1934) and Wielenga (1937), however, consider it possible 

 to distinguish three species on the basis of biochemical activity, (a) The least active 

 and the least variable comprises the rhinoscleroma strains, which have the following 

 reactions : they form no gas from carbohydrates, they produce acid in glucose, maltose, 

 mannitol, and adonitol in 24 hours, in sucrose within 10 days, and sometimes in glycerol, 

 they do not ferment lactose, dulcitol, or amygdahn within 3 days, they have no action 

 on htmus milk, they usuaUy produce alkali in neutral peptone water in 10 days, they 

 are M.R. positive and V.P. negative, they do not grow in citrate or d-tartrate, they do 

 not grow in fresh ox bUe, and they form no HjS. (6) The second group, comprising the 

 ozsena strams, is simUar in most respects, but there is more variability between the different 

 members. Most strains fail to produce gas from carbohydrates, but some do ; they 

 produce acid and sometimes gas from glucose, maltose, mannitol, and adonitol in 24 hours, 

 many strains from lactose or amygdalin within 3 days, but the majority fail to ferment 

 sucrose within 10 days and none ferments dulcitol, many strains produce acid and some- 



