]06 POULTRY DISEASES 



that tlu' glands wliich were active during the feeding of the 

 young suddenly eea.sed l^eing used and heeame intlanied. 



S y nipt his. — There is a loss of appetite. Tlie bird appears 

 dull, stretches its neck repeatedly and swallowing becomes 

 difficult. The crop is tender to pressure, soft to the touch 

 and at times, gaseous. Pressure on the crop may cause fetid 

 gases to escape from the mouth. Repeated attacks cause the 

 development of pendulous crop. 



Treatment. — If the crop be distended with a dough-like 

 mass, grasp the bird by the legs, holding the head downward, 

 gently press out the mass ; then by introducing water through 

 the mouth and forcing it out as before, the crop, in this way, 

 may be washed out. 



Give bland substances, such as gruel and mild antiseptics, 

 such as salol, subnitrate of bismuth or sulphocarbolates com- 

 pound. 



DEPRAVED APPETITE (PICA) 



This may be due to a disease of the digestive organs or it 

 may be a vice learned from others. Hens learn to eat eggs 

 by finding them broken or by seeing an egg-eating hen and 

 copying as a cril)bing horse acquires the habit from his mate, 

 or as one hog may learn to eat chickens from seeing another 

 eating one. 



Feather eating (plucking) is another habit that may be 

 acquired from mimicry. Obstruction of the gizzard, lack of 

 grit, insufficient or unsuitable food and catarrh of the crop 

 are factors of greater or less importance in causing a depraved 

 appetite. Kill the bird; the habit cannot be broken. 



CHICKEN CHOLERA— FOWL CHOLERA 



Fowl cholera is caused by a germ {BariJlus avisepticiis) . 

 and is a blood-poisoning (septicemia). The germ is rather 

 short, plump, and stains at the poles or ends deeper than the 

 middle, with arpieous fuchsin, hence it is called a ]K)]ar-stain- 

 ing ])acillus. Fig. 44 shows the germ, magnified 1. 000 times. 

 This drawing was nu^de from a blood smear from an outbreak 

 among turkeys and chickens, which was one of several out- 

 breaks that have been studied in the author's laboratory. The 

 large objects are various kinds of blood cells. One of these, 

 a white-blood cell (i)hagocyte), has taken up one of the germs. 



Mode of Spread. — Birds often contract this disease from 

 others at shows, and when taken l)ack home infect the re- 

 mainder of the flock aiul the premises, or a bird recently pur- 

 chased from an infected flock, or eggs from an infected flock, 

 or chicks recentlv liatched in infected suri'oundings, oi- in- 



