252 THE POULTRY-BOOK. 



cooperate with her ; and the aim of all medical treatme e 

 should be to follow the indications which nature holds out, 

 and assist in the effort which she constantly makes for the 

 restoration of health. 



Before treating in detail the maladies of greatest conse- 

 quence, it is desirable to present a brief view of so much of 

 the anatomical structure of fowls as will be necessary to the 

 comprehension of disease and its management. 



The digestive function in poultry is partly mechanical and 

 partly chemical. In its several stages, it differs widely from 

 that of some quadrupeds who feed on similar food. In these, 

 grains are frequently swallowed without being crushed by the 

 teeth, and as their stomachs have not the power of digesting 

 solid grain, it is voided whole. In fowls, on the other hand, 

 the grain is all swallowed whole, and it is digested in the 

 stomach. From this fact, the opinion has been derived of the 

 necessity of giving stones and gravel to fowls, in order to ena- 

 ble them to grind the food which they take. But this is a 

 vulgar error ; for, though there are advantages derived from 

 furnishing facilities to a flock to pick among gravel, it is by no 

 means necessary to a perfect and regular digestion. 



The digestive organs of fowls consist of the gullet and crop, 

 the gizzard, stomach, liver, and intestines. The gullet, or 

 aesophagus, runs down the neck towards the right side, swel- 

 ling out, in front of the chest, into a membraneous bag, which 

 is called the crop or craw. 



The crop is somewhat analogous to the paunch in the ox or 

 sheep. It receives the gullet into its upper part, and proceeds 

 downwards, about the middle of the bag, in such a manner 

 that the crop is in some measure aside from the regular com- 

 munication between the upper and lower opening of the gullet. 

 Its office is to receive the food when first swallowed, and to 

 macerate it, and dissolve it by means of a liquor, which is 



