Dec. 8, 1906 .1 
FOREST AND STREAM. 
901 
Food Tube of Dog. 
(From Flower). 
Gullet 
[Esophagus) 
Stomach 
Intestine 
Rectum 
Intestine 
Anus 
/ 
Stomach 
— Rectum 
__ Gullet 
Fig. 3. 
Food Tube of Fish (Perch). 
(From Wiedersheim). 
or masticated a second time, and that is the mean¬ 
ing of the first or largest pouch at the right of 
the sheep’s stomach as you look at it, known 
as the paunch, which is simply a storage bag, 
where the grass and leaves, taken in by the sheep 
while grazing, can be stored until the animal has 
time to lie down in a quiet place and devote its 
entire attention to, as we say, “chewing the cud,” 
or masticating carefully for a second time the 
food, as it is returned to it from the first pouch 
of the stomach. This is what is known 
as ruminating and has given the name ruminants 
to this class of animals. Curiously enough, from 
the fact that, sheep and cows look so peaceful 
and meditative while they are going through with 
the second eating of their food which they seem 
to enjoy thoroughly, the term has actually been 
applied to the mental process in ourselves known 
as “thinking over things.” _ 
From this second grinding the cud is passed 
back through the second and third stomachs 
where it undergoes a sort of churning process 
and then passes into the last compartment of 
the stomach (to the left of the picture) which 
corresponds to almost the entire digestive 
stomach in the dog and in ourselves. Indeed if 
you will look closely you will see that it is 
nearly the same pear shape as the greater part 
of the dog’s stomach. 
Now let us turn to the small intestine. At 
first sight this appears entirely unchanged, but 
it looks somehow much more complicated and 
if we proceed to measure its length, we find 
that it is nearly three times that of the dog’s 
intestines, that is to say, while this part of the 
food tube in the dog is from four to six times 
the length of his body, in the sheep it is from 
twelve to fifteen times the body length, and this 
is only what we would naturally expect, when 
Gullet 
-Stomach 
>-Intestine 
'Fig 4.—Stomach of Sheep. (From Oppel.) 
a. Gullet Esophagus: b. c, d , the three subdivisions of the paunch, marked off from 
one another by the folds e and/; g , reticulum: h, cesophageal groove;/, psalte- 
rium; k, aperture leading from the psalterium into the abomasum (/, m): n , 
pyloric valve; o , intestine. 
Crop 
Double 
appendix 
[CcecuMi) 
Rectum 
Fig. 2 
Food Tube of Newt 
(From Wiedersheim) 
showing simplicity and 
straightness. 
we remember that it has to deal with food that 
is much more difficult of digestion and conse¬ 
quently requires a longer absorptive surface to 
soak it up completely. The second or larger 
part of the intestine differs from that of the 
dog only in this same direction of being longer 
and slightly more complicated, to match the 
more watery character of the food. The shape 
and length of the food tube in different animals 
match quite closely the character of their food, 
just in the same way as do their teeth. By look¬ 
ing at an animal’s teeth you can usually tell 
quite accurately not only what sort of food he 
lives on, but also what sort of stomach and 
about what length of food tube he has. 
A curious proof of the close relation between 
teeth and food tube is to be found in those 
toothless “animals” the birds. These, as you all 
know, have no teeth but simply a horny cover¬ 
ing of the jaws known as a beak. In the birds 
of prey this beak is curved and sharp, so as to 
be capable of tearing up the food to some ex¬ 
tent, but in the greater majority, of birds, both 
those who live on grain and seeds, and those 
who live on insects, the beak is simply a quick¬ 
acting pair of pincers for picking up the corn 
and catching the insects, which are then swal¬ 
lowed whole. 
How then is their food canal to manage food 
in large, hard pieces like this, which has never 
been ground by teeth before it is swallowed? 
As everywhere else in the animal kingdom, 
nature is ready with a substitute. Instead of 
teeth, moved by powerful jaw muscles, developed 
at the opening of the canal to form a grinding 
apparatus, near the middle of it, just beyond or 
more exactly in the last portion of the stomach, 
we find a thick, hard globe, about the size of a 
walnut in a fowl, for instance, known as the 
Gizzard 
Anus and 
Cloaca 
Intestine 
Fig. 5.—Food Tube of Bird. 
(From Holder). 
gizzard. On cutting into this we find, little as 
it looks like it from the outside that it is really 
a pouch with immensely thick walls, made up of 
strong muscle, and tendon and lined with a thick 
leathery, almost horny, layer. The small hollow 
in the center of the pouch is usually filled with 
bits of gravel and pebbles. 
What can be the use of such a strange look¬ 
ing structure as this? If you would clasp your 
two hands together as if you were about to wash 
them in imaginary soap and water, then drop 
into the hollow between the palms a piece of 
chalk, say, a lump of hard clay and rub it back¬ 
ward and forward between the palms, you will 
find that you can break it up into small pieces 
and gradually to powder. If, however, you drop 
in three or four other small pieces of chalk or 
dry clay and especially one or two pieces of 
squarish bits of stone, or any small object with 
a rather rough surface and some corners on it, 
you will find that you can grind the clay or 
chalk into powder nearly twice as rapidly, and 
that you can even break up grains of corn, thin- 
shelled hazel nuts and walnuts in this curious 
form of mill, and this is precisely the meaning 
•and action of this tremendously thick-walled 
