POULTRY DISEASES 
5 
THE NORMAL VISCERAL ANATOMY OF THE HEN 
Digestive and Genito-Urinary Tracts 
At 1 is the beak; 2, the tongue; 3, the pharynx (throat), through which 
the food passes to the oesophagus or gullet (4); 5, the crop, a storehouse or 
granary where the food accumulates during feeding. From the crop the 
food passes through the second portion of the oesophagus; 6, a part of the 
abdominal organs laid over to the left so that the proventricukus or true 
stomach (7), lays over the liver (26). The second portion of the oesophagus 
empties into the proventriculus in whose walls are found secreting glands 
similar to those in the true stomach of higher animals. The food, after being 
soaked in this fluid, passes into the gizzard (8), a muscular organ, where 
the grain and other coarse particles are ground with the aid of grit by the 
contractions of the muscular walls. From here the food passes into the 
duodenum (9). At 10 is shown the loop of the first portion of the small 
intestines in which is located the pancreas (25), which pours its digestive 
secretion into the small intestines. At 11 is represented the floating portion 
of the small intestines, supported by the mesentary, a web-like membrane 
(19) carrying the blood vessels in their course to that part. Numbers 12 
and 13 represent the caeca or two blind guts, the blind extremities being at 
13. These empty into the balance of the intestine at 14. At 15 is shown 
the rectum or straight gut, which is joined by the egg sac (23) at 17, forming 
the cloaca or common pouch (16). At 20 the ureter from the kidney (21) 
empties the secretion from that gland into the rectum. The cloaca com¬ 
municates through the anus (18) with the external world. The right ovary 
perishes as the hen develops so that only one ovary, the left, remains, which 
is indicated by 22. The egg canal (23) has a muscular wall for the purpose 
of forcing the egg along as it develops; it is also provided with glands which 
aid in the formation of the albumin, egg shell, etc. This sac at its anterior 
end receives the ovum (yolk) from the ovary as soon as it is mature. At 
2 6 is seen the liver, which has been turned back and is crossed by the pro- 
ventriculus (7). At 27 is the gall bladder, where the bile (liver secretion) 
is stored up till active digestion takes place in the small intestines when it is 
poured out into the latter. At 2 8 is the spleen, a blood forming organ. 
The Respiratory Tract and Heart. 
The air passes from the nostrils (29) through the nasal passage, in¬ 
dicated by the dotted line, enters the pharynx through the opening (posterior 
nares) at 33; 32 is the turbinated bone of the right nasal chamber; 30, the 
frontal, and 31, the maxillary (infra-orbital) sinuses, analagous to the same 
in the higher animals. The air passes through the pharynx (3) into the 
larynx (35) through the opening or glottis (34). From the larynx the air 
passes through the trachea or windpipe (36). At 37 there is noted a flat¬ 
tened portion, the false larynx, provided with vocal cord-like structures— 
the organ of sound. Just below this point will be noted the bifurcation 
(branching) of the trachea to the lungs. At 38 is the left lung. The heart is 
pulled down so that these parts are brought into view. At 3 9 is the heart; 
40, the main artery (aorta) leading from it; 42, its branch supplying the 
neck and head; and 41, the left wing. 
PARASITIC DISEASES 
LICE 
There have been four genera of lice studied in this laboratory, namely, 
Menopon, Goniodes, Goniocotes, and Lipeurus. 
THE LARGE HEN LOUSE—Menopon biseriatum. This is the largest 
louse found upon the hen. It is about one-twelfth of an inch in length, light 
in color, with mouth parts arranged for mastication as illustrated in Fig. 2-a. 
The free extremities of the legs are provided with hooklets which aid in hold¬ 
ing on. 
