DISEASES OF THE DIGESTIVE ORGANS. 49 



Plate III. — Instruments used in treating diseases of digestive organs — Contd. 

 drawn, and the temperature read as in any ordinary thermometer. The 

 clinical thermometer is made self-registering; that is, the mercury in 

 the stem remains at the height to which it was forced by the heat of 

 the body until it is shaken 'back into the bulb by taking hold of the 

 upper portion of the instrument and giving it a short, sharp swing. 

 The normal temperature of cattle varies from 100° to 103° F. In 

 young animals it is somewhat higher than in old. The thermometer 

 is a very useful instrument and frequently is the means by which 

 disease is detected before the appearance of any external sign. 



Fig. 2. Simple probang, used to dislodge foreign bodies, like apples, pota- 

 toes, eggs, etc., which have become fastened or stuck in the esophagus 

 or gullet. 



Fig. 3. Grasping or forceps probang. This instrument, also intended to 

 reiuove obstructions from the gullet, has a spring forceps at one end in 

 the place of the cup-like arrangement at the end of the simple probang. 

 The forceps are closed while the probang is being introduced ; their 

 blades are regulated by a screw in the handle of the instrument. This 

 probang is used to grasp and withdraw an article which may have 

 lodged in the gullet and can not be forced into the stomach by \ise of 

 the simple probang. 



Fig. 4. Wooden gag, used when the probang is to be passed. The gag is a 

 piece of wood which fits in the animal's mouth ; a cord passes over the 

 head to hold it in place. The central opening in the wood is intended 

 for the passage of the probang. 



Figs. 5a and 5b. Trocar and cannula ; 5ff shows the trocar covered by the 

 cannula ; 5b, the cannula from which the trocar has been withdrawn. 

 This instrument is used when the rumen or first stoiuach becomes 

 distend(Hl with gas. The trocar covered by the cannula is forced into 

 the rumen, the trocar withdrawn, and the cannula allowed to remain 

 untl! the gas has escaped. 



Fig. 0. Section at right angles through the abdominal wall, showing a 

 hernia or rupture. (Taken from D'Arborval. Dictionnaire de M?(lecine, 

 de Chirurgie de Hygiene) : a a, The abdominal muscles ciit across; v, 

 opening in the abdominal wall permitting the intestines i i to pass 

 through and outward between the abdominal wall and the skin ; p p, 

 peritoneum, or membrane lining the abdominal cavity, carried through 

 the opening o by the loop of intestine and forming the sac S, the outer 

 walls of which are marked b f b. 

 Plate IV. Microscopic anatomy of the liver. The liver is composed of innu- 

 merable small lobules, from -j^-^ to tij inch in diameter. The lobules 

 are held together by a small amount of fibrous tissue, in which the 

 bile ducts and larger bloml vessels are lodged. 



Fig. 1 illustrates the structure of a lobule ; v v, interlobular veins or the 

 veins between the lobules. These are branches of the portal vein, 

 which carries blootl from the stomach and intestines to the liver ; c c, 

 capillaries, or very fine blood vessels, extending as a very fine network 

 between the groups of liver cells from the interlobular vein to the 

 center of the lobule and emptying there into the intralobular vein to 

 the center of the lobule ; v c, intralobular vein, or the vein within the 

 lobule. This vessel passes out of the lobule and there becomes the 

 sublobular vein ; v s, sublobular vein. This joins other similar veins 

 and lielps to form the hepatic vein, through which the blood leaves 

 33071°— 16 4 



