THE FRIEDLANDER GROUP 667 



as white scours, and the fatal septicsemia that may sometimes accompany it, to 

 infection with Bact. eoli (see also Lovell 1937). They found that the disease was 

 prone to occur in calves fed on milk instead of colostrum. It is possible that the 

 neonatal diarrhoea of human infants may result from the access to the intestine of 

 specially virulent forms of Bad. coli, but the available evidence is as yet insufficient 

 to afford conviction (see Chapter 71). According to Gwatkin, LeGard and Hadwen 

 (1938) bovine mastitis may occasionally be due to coliform bacilli. 



The pathogenicity of most strains for laboratory animals is low. Very large 

 doses administered intraperitoneally to the mouse, or intravenously to the rabbit, 

 may prove fatal ; but it seems likely that death results in these cases from a toxaemia 

 rather than from a true infection. Occasionally strains of greater virulence are 

 found. 



Several observers have described the presence of soluble toxic substances in 

 young broth cultures of Bact. coli (see, for instance, Steinberg and Ecker 1926, 

 Smith and Little 1927, Smith, D.E., 1927, Rennebaum 1935). But most of 

 these " toxins " have proved to be heat-stable, and there is no reason to believe 

 that they differ from the toxic components that can be extracted, in larger quantity, 

 from the bacterial cells. Since there is at the moment no clear evidence that 

 the toxic substances that can be extracted from the colon bacillus differ in their 

 action from those of other species within this genus, a discussion as to their probable 

 nature may be deferred to a later section. 



The Friedlander Group 



There are certain species of lactose-fermenting coliform bacilli which cannot 

 readily be placed in any of the groups which we have differentiated above. There 

 are, for instance, the so-called capsulated bacilli, including Friedlander's pneumo- 

 bacillus, Abel's bacillus of ozsena, the bacillus of rhinoscleroma, and others. There 

 appears to be a preponderance of opinion that the organisms of this group are in 

 some way related to Bact. aerogenes, principally because that organism is sometimes 

 capsulated ; but the fermentation reactions, as described by those who have isolated 

 and studied these capsulated coliform bacilli, appear to be extremely variable, and 

 several observers have recorded the fermentation of saccharose, but not of lactose. 

 The balance of evidence suggests that these strains should be included in the genus 

 Bacterium, but it is convenient in the meantime to consider them in a separate 

 sub-section of this group. 



Group Characteristics. 



Short, non-motile, non-sporing, capsulated Gram-negative rods, giving a profuse 

 mucoid growth on solid media, and usually fermenting carbohydrates with the 

 jiroduction of acid and gas. Usual habitat, respiratory tract of man and certain 

 animals. 



Under the general term B. mucosus capsulatus a large number of organisms 

 have been described with the characteristics enumerated above. V. Frisch in 

 1882 isolated a capsulated bacillus from patients with rhinoscleroma. In 1883 

 Friedlander cultivated a similar organism — generally known as Friedlander's 

 bacillus or Bact.friedldnderi — from the lungs of patients who had died of pneumonia. 

 Loewenberg in 1894 and Abel in 1896 cultivated a similar organism from the nasal 

 secretion of patients with ozsena. Besides these, several organisms have been 

 described by other workers, such as B. pseudopneumonicus Passet, B. canalis 



