20 
THE COLORADO EXPERIMENT STATION 
Fig- 21 Fig. 22 
Figure 21.—A transverse section through the caecum of a chick that died of 
white diarrhoea; a, muscular layer which, at some points, is invaded by the pro¬ 
tozoan, Coccidium tenellum. The glands of the mucous membrane have all dis¬ 
appeared except small remnants indicated by b; c, granular degenerated mass 
from dissolution of the mucous membrane, magnified 100 times. 
Figure 22.—The area in the circle indicated by b in Fig. 21, magnified 900 
times. The letters indicate the protozoon parasite in various stages of develop¬ 
ment; a, oocyst; b, first stage of sporoblast; c, first stage of sporozoit; d, the 
schizont showing within the merozoits. These are surrounded by a disintegrating 
cell mass; e, shows white blood cells (polymorphonuclear neutrophiles). 
nants of a few glands normally present are yet intact, the balance of the 
mucous membrane, and in places the submucous layers, are invaded by the 
germ. In Fig. 22, section B has been magnified 900 times. As explained 
under the cut, all stages of the organism are observed in a mass of dying 
and disintegrating cells, the remains of the diseased mucous lining of the 
bowel. Repeated examinations have been made of healthy chicks killed for the 
purpose, and chicks dying from other causes and, thus far, no case has shown 
these conditions. 
TREATMENT.—Unsanitary conditions, spoilt food, dirty stagnant water, 
improperly ventilated incubators, brooders and buildings, or badly regulated 
heat are factors in weakening the physical condition of chicks and favor 
ravages of disease. 
Most of our experimental work with various remedies has been with the 
coccidian form. In one outbreak referred to above, 80 per cent of the first 
2,000 chicks had died. We began trying to improve sanitary conditions, and 
administered various dilutions of permanganate of potash, copperas and car¬ 
bolic acid. The loss was unaffected. By this time the writer had examined 
many dozen of birds in the laboratory, and in about 50 per cent of the cases 
the organism (Bact. pullorum) was isolated from the heart, blood, liver, 
spleen and kidneys, and in every case the coccidian ulcers described above 
were observed. These chicks began dying in numbers when about ten days 
old, very few dying before that time, and from this period to the end of the 
third week the great loss occurred. After this time but few died, but those 
having the disease in light form were stunted and did not make satisfactory 
growth. 
With this data before me, I began on another line of treatment. For 
the past ten years I have used, to some extent, dilutions of bi-chloride of 
mercury as an intestinal antiseptic in chickens. This was used in this out¬ 
break in a 1 to 10,000 dilution with sulphocarbolates of zinc, sodium and 
calcium. The latter had not given the satisfactory results when used alone 
