120 POULTRY DISEASES 



hatched. This may be explained l)y tlie fact that hens with 

 diseased ovaries gradually become poorer layers as the disease 

 processes advance, and lience, only lay in late spring or early 

 summer, when nature intends reproduction of birds. Finally 

 the hen may cease laying. 



Symptoms: Cocciclian Form. — The symptoms, as I have 

 seen them, are similar to those of the bacillary form, except- 

 ing, as a rule, the heavy death rate takes place later. 



Mode of Spread: Bacillary i^orm.— Ovaries of laying hens, 

 diseased, but still functioning, may be infected by the germ. 

 The germ can be isolated, particularly from the yolk, of at 

 least some of the eggs formed in such an ovary. The chicks 

 from infected eggs, as a result, have the disease more or less 

 developed when they are hatched, as conditions which favor 

 hatching also favor the multiplication of the germs to an ex- 

 tent that toxins (poisons) have already been produced in the 

 young in sufficient quantity for the disease to at least mani- 

 fest itself in a few hours after hatching, although ordinarily 

 they do not begin to die until they are about a week old. 



The whitish, frothy, pasty bowel discharge, more or less 

 sticky and having a tendency to "paste up the vent," from 

 these chicks is laden with the germs, and others of the flock 

 soon become infected from contaminated food picked up from 

 the ground. In the former case, chicks may begin to die soon 

 after hatching; in the latter, in from three to four days, a 

 few dying each day. 



The death rate is high, reaching in many cases as much as 

 seventy-five per cent or more. Those that recover are stunted 

 and do not make satisfactory growth. The greatest loss is 

 from the first few days to, in some cases, two or three weeks. 

 It is probable that the carriers are chicks that have recovered, 

 but which still carry the organism (especially in the ovary) 

 as the human typhoid carriers carry the germs of typhoid 

 fever, in the infected kidneys and in bowel ulcers. These ' ' car- 

 riers," having established an immunity, do not themselves 

 succumb to the disease, and they rarely show any outward 

 symptoms of it. 



" Insanitary conditions, spoiled feed, dirty, stagnant water, 

 improperly ventiUited incubators, brooders and buihlings,^ or 

 badly regulated heat, are factors in weakening the physical 

 condition of chicks and favor ravages of diseases. 



Coccidian Form.— The mode of spread of this form is at 

 present prol)lematical. It is possible that a chronic type of 

 coccidiosis occurs in some bii-ds and thus perpetuates and 

 disseminates the protozoa. 



Postmortem Findings: bacillary form. — The liver in general is 



