i88 POULTRY dise;ase;s and their treatment. 



intestines. In older birds it is obscured by the. common and rap- 

 idly growing intestinal organisms, particularly the colon bacil- 

 lus." 



Dr. Rettger has also been able to find this same organism "in 

 (a) the ova in the ovaries of the hens, (b) the yolk of fresh 

 laid eggs, (c) eggs incubated for varying lengths of time and 

 (d) yolk sacs of fully developed chicks still within the shell." 

 This, together with the evidence that the organism does produce 

 white diarrhea, shows pretty conclusively that one source of 

 infection is the hen. The feeding experiments with pure cul- 

 tures of the bacillus apparently show that the infection must 

 begin within the first 48 hours after the chicks are hatched. 

 Several investigators have shown that it is impossible to infect 

 chicks by feeding after they are two days old. It may be said 

 that Dr. Rettger has proven that at least one form of white 

 diarrhea is caused by a bacterium. The relation of this form 

 of the disease to that caused by other organisms is still a subject 

 for investigation. 



Diagnosis. The external symptoms of bacillary white diar- 

 rhea are much the same as those given for the disease in gen- 

 eral (cf. p. 189)- The following post-mortem appearances are 

 reported by Rettger and Stoneburn : — 



''Crops — Empty or partially filled with slimy fluid or with 

 food." 



'Xungs — Apparently normal. (Tubercles not observed)." 



'Xiver — Pale, with streaks and patches of red. These appar- 

 ently slightly congested areas are usually large in size." 



"Kidney and Spleen — Apparently normal." 



"Intestines — Pale, and for the greater part empty. A small 

 amount of dark grayish or brownish matter frequently present." 



"Ceca — With few exceptions but partially filled with a gray- 

 ish soft material. Only occasionally cheesy or firm contents." 



"Unabsorbed Yolk — Usually present varying in size from a 

 pea to a full-sized yolk. The color may vary from yellow to 

 brownish green or nearly black. In consistency there is also 

 much variation. It may appear perfectly normal, distinctly 

 gelatinous, or watery. Frequently it is observed in the char- 

 acter of custard and again more or less dry and firm. Unless 

 the chick has been dead for some time the yolk is usually not 

 found putrid, but merely stale." 



