BACTERIUM PULLORUM 295 



the cause of this affection, Rettger and Harvey have described a 

 specific organism, which, according to its morphologic and cultural 

 properties, belongs to the colon-hog-cholera group of bacteria. 



Pathologic Lesions. The chicks on postmortem examination are 

 found to be much emaciated; the crop is empty, the intestines are pale, 

 but without indications of ulceration or congestion, and the liver is 

 pale, with the exception of a few patches and streaks which are of a 

 dark color, while the spleen, lungs, and kidneys appear normal. In 

 stained sections of the tissues small slender bacilli are occasionally 

 found. These organisms do not occur in groups, but singly, scattered 

 here and there through the section. While in healthy chicks or in 

 those which have died from other causes the yolk is generally com- 

 pletely absorbed at this age, in chicks dead from white diarrhea 

 the yolk sacs are not yet absorbed, but are present, varying in size from 

 a small pea to an Italian chestnut. According to Rettger and Harvey 

 the best method of obtaining the organism in first culture is to open 

 the body with a sterile knife, then remove as much blood as possible 

 with a sterile platinum loop; also pieces of spleen or liver, or some 

 of the contents of the unabsorbed yolk sac, and make streaks on agar 

 slants. The latter are to be incubated at 35 to 37 C. In the course 

 of twenty-four hours, inspection, preferably with a hand magnifying 

 lens, will reveal the presence of minute colonies which resemble small 

 droplets of fat. The colonies are discrete, and remain so even after 

 several days of incubation. The colonies never grow to be large, 

 although there is considerable increase in size after the first twenty- 

 four hours. The growth on agar streaked with the infected blood 

 during the first twenty-four to thirty-six hours has all the appearances 

 of the ordinary streptococcus. 



Morphology. The Bacterium pullorum, isolated by Rettger and 

 Harvey from white diarrhea, or septicemia of chicks, is a long, slender 

 bacillus, 3 to 5 micra long by 1 to 1.5 micra wide, with slightly rounded 

 ends. It usually occurs singly, chains of more than two bacilli being 

 rarely found. It is non-motile, and resembles the bacillus of typhoid 

 fever. It is stained readily by the ordinary watery anilin stains, and 

 is Gram negative. It does not form spores. 



Cultural Properties. The colonies on agar slants have been already 

 described. On gelatin plates it forms surface colonies which some- 

 what resemble the grape-leaf colonies of the typhoid bacillus. In 

 gelatin stick cultures a delicate growth appears in forty-eight hours 

 along the whole line of inoculation; the growth is distinctly granular 

 in appearance, and spreads very little on the surface. Gelatin is 

 not liquefied. The development on potato is slow; in litmus milk 

 there is no change for forty-eight hours, then the medium becomes 

 slightly acidified, but there is no coagulation. The organism can split 

 dextrose and mannite with acid and gas production, but it does not 

 ferment either maltose, lactose, saccharose, inulin, or dextrin. It 

 does not form indol or nitrite in Dunham's solution. 



