DISEASES OF POULTRY. 229 



tissues of fowls is from 1.2 to 1.8 micro -millimeters 

 long and 1 to 1.3 micro -millimeters broad. It fre- 

 quently appears in small clumps, but as a rule is in 

 pairs united end to end. This germ is found in the 

 blood and in various organs of the body. 



Experimentally the disease has been produced by 

 inoculating with pure cultures of the germs and by 



feeding pure cultures 



or the organs of 



affected fowls. The 



injection of 0.3 cubic 



,.^.. centimeter of a fresh 



» culture into the wing 



ft ^^^p vein caused the dis- 



■*" ease and death in 



^r i^"'""-'^ from three to thirteen 



I i' days ; usually on the 



Fig. 10.— Bacterium smiguinarium from h'th or SlXth day. 



spleen of rabbit. Feeding cultures or 



viscera of afiected birds was followed by death in 

 from seven to fifteen days, but only about half of the 

 birds fed contracted the disease. Pigeons, rabbits, 

 guinea pigs and mice contract the disease if inoculated 

 with 0.2 to 0.3 cubic centimeter of culture and die 

 within three to six days. 



It appears probable from these investigations that 

 the contagion in natural outbreaks is taken into the 

 body with the food, but the disease is not readily 

 propagated under sanitary conditions. Healthy fowls 

 placed in cages with diseased ones did not in a single 

 instance contract the disease. When cultures of the 

 germs and diseased viscera were fed, only about one- 

 half of the fowls became affected. Notwithstanding 

 this, nearly all of one flock of about fifty fowls near 



