MICROBIAL DISEASES OF MAN AND DOMESTIC ANIMALS 755 



white diarrhoea," is caused by a bacterium which belongs to the colon- 

 tjrphoid group of organisms. It may be cultivated easily on the ordi- 

 nary laboratory media, but its growth on slant agar containing ^itte's 

 peptone is delicate and bears a striking resemblance to that of Strepto- 

 coccus pyogenes. This finely beaded growth is an important aid in 

 the identification of the bacterium. 



The specific organism, Back pullorum, is present in the liver, lungs, 

 kidneys, spleen, heart and unabsorbed yolk of affected chicks, being 

 most easily obtained from the Uver and yolk, when the latter is present. 

 Some of. the most common post-mortem appearances of the organs are 

 those of the Uver and intestine, the former showing pale and congested 

 areas, while the intestine is colorless and to a large extent void of 

 contents. 



The disease seldom manifests itself in chicks after they have attained 

 the age of four or five weeks. The greatest mortahty usually occurs 

 within the first two weeks. The chicks become listless, and are inclined 

 to huddle together for warmth. There is loss of appetite and emacia- 

 tion. The wings droop, the back seems to shorten and the abdomen 

 protrudes out of proportion, causing the chicks to look stilty. The 

 characteristic whitish discharge from the bowel may be absent from 

 individual chicks, but is usually noticeable in groups of any appreciable 

 size. 



Bacillary white diarrhoea may be transmitted to young chicks under 

 five days old through infected food and drinking water, as has been 

 ' demonstrated repeatedly. Furthermore, chicks are often infected with 

 Bact. pidlorum before they are hatched. This is due to the fact that 

 the yolk of infected hens carries the specific organism in it from the time 

 of its formation in the ovary. Hence, the mother hen is the source of 

 infection, having retained within it the bacterium in question from the 

 time she was an infected chick, or having acquired it later in life through 

 contact with diseased fowls. In laying hens the infection is localized 

 in the ovary which becomes decidedly abnormal in appearance. The 

 partly developed ova are discolored, misshapen and of all degrees of 

 consistency. 



Ovarian infection may be determiifed by the macroscopic agglutina- 

 tion test which has proven itself very valuable and practicable in the 

 organized campaign against bacillary white diarrhoea that has been 

 conducted in the State of Connecticut for the past two years. This 



