l82 POULTRY DISEASES AND THEIR TREATMENT, 



system of chicks under 3 weeks oltl is. so delicate that even a 

 slight disturbance makes a very serious handicap for the chick. 



Etiology. Within recent years a large number of studies 

 concerning the cause, prevention and cure of white diarrhea 

 have been conducted. Investigations have been carried on by 

 state and national institutions as well as by many private in- 

 (hviduals. Consequently a large number of alleged causes of 

 the disease are given by dififerent writers. Among these may 

 be mentioned : Debilitated breeding stock, improper incuba- 

 tion, improper brooding, overheating, cliilling, poor ventilation, 

 over-crowding, poor or improper food and filth as well as spe- 

 cific bacteria, fungi or other parasitic organisms. 



Dr. Geo. B. Morse in the Reliable Poultry Journal for July, 

 1909, classifies the causes of diarrhea in chicks as follows: 



"First among these causes is the class of physical agents. 

 Under this title I would place such agencies as heat or its lack, 

 moisture or its lack, producing what we call in human medi- 

 cine, the diarrhea of relaxation. Such a condition is produced 

 in the intestinal tract that a large amount of serum is driven 

 through the intestinal wall into the lumen of the intestine, and 

 in doing so the cells are loosened, antl thus we have the devel- 

 opment of a catarrh. This condition may be brought about by 

 the agencies just mentioned." 



"Another class of agencies may be designated foreign bodies, 

 and in this class I place such diarrheas as originate from im- 

 proper feeding, too early feeding or feeding wrong material. 

 W'c know, from analogy, that in mammalians whether human 

 or the lower animals, such a condition is possible." 



"Then we have another large class of intestinal derangements 

 01 catarrhs or inflammatory conditions produced by what we 

 call living agents or parasites. These produce what we may call 

 parasitic inflammations. Now, we must subdivide this class 

 into two, and we may get rid of one substance at once by placing 

 in it those catarrhs or inflammations produced by the larger 

 parasites, macroscopic parasites, such as worms." 



"Thus we come to the other sub-class of parasites causing de- 

 rangements in the intestines, the microscopic parasites or micro- 

 organisms. This sub-class of diarrhoea-producing micro-organ- 

 isms falls naturally into 3 groups. Having already referred to 

 the animal kingdom in speaking of worms we shall take our 

 first group of parasitic micro-organisms from that same king- 



