115 



treatment fails, try the following combination, recommended by a 

 good authority: Hydrocyanic acid (Sclieele's strength), 20 minims; 

 nitrate of x)otassium, 3 drams; bicarbonate of soda, 1 ounce; water, 

 1 pint. This dose should be given every morning and evening for one 

 or two weeks, if necessary. 



The diet should be the most nourishing. Bad food is harmfid at 

 any time, but especially in this disease. Avoid bulky food. Linseed 

 mashes, scalded oats, grass and green-blade fodder, if in season, is 

 the best diet. 



THE LUNGS. 



The lungs are the essential organs of respiration. They consist of 

 two (right and left) spongy masses, commonly called the "lights," 

 situated entirely within the thoracic cavity. On account of the space 

 taken uj) by the heart, the left lung is the smaller. Externally, they 

 are completely covered by the pleura. The structure of the lung con- 

 sists of a light, soft, but very strong and remarkably elastic tissue, 

 which can only be torn with difficulty. The lung of the fostus v,iiich 

 has never respired will sink if placed in water, but after the lung has 

 been inflated with air it will float on water so long as healthy. This 

 fact is made useful in deciding whether or not an animal was born 

 dead or died after its birth. Each lung is divided into a certain num- 

 ber of lobes, which are subdivided into numberless lobules (little 

 lobes). A little bronchial tube terminates in every one of these small 

 lobules. The little tube then divides into minute branches which 

 open into the air-cells (pulmonarj'^ vesicles) of the lungs. The air- 

 cells are little sacs having a diameter varj^ing from one-seventieth to 

 one-two-hundredth of an inch; they have but one Oliening, the com- 

 munication with the branches of the little bronchial tubes. Small 

 blood-vessels ramify in the walls of the air-ceUs. The walls of the air- 

 cells are extremely thin and consist of two layers; the blood-vessels, 

 being between the laj'ers, thus expose a surface to the air in two 

 different cells. The air-cells are the consummation of the intricate 

 structures forming the respiratory apparatus. They are of prime 

 imjiortance, all the rest being complementary. It is within these cells 

 that is accomplished all that constitutes the ultimate result of the 

 function of respiration. It is here the exchange of gases takes place. 

 As before stated, the walls of the cells are very thin; so, also, are 

 the walls of the blood-vessels. Through these walls escapes from the 

 blood the carbonic-acid gas that has been absorbed by the blood in 

 its circulation through the different parts of the body; and through 

 these walls is absorbed by the blood, from the air in the air-cells, the 

 oxj'^gen gas, which is the life-giving element of the atmosphere. 



Throughout the substance of the lungs the bronchial tubes terminate 

 in the air-cells. Blood-vessels are in every part; likewise lymphatic 

 vessels and nerves, which require no more than mention in this pax)er. 



