"I am inclined to favor the hypothesis that pleuro-pneumonia is produced by animalculae, and that these enter the lungs by myriads, and thereby set up irritation and inflammation, which lead to all the phenomena and pathological conditions which are to be found upon dissection. This is my opinion of the cause of the malignant pleuro-pneumonia which has existed in the United States for the last seven years." After writing the foregoing, the author was informed that this disease had made its appearance in Mr. Logan's herd, already mentioned as exposed. He was called to visit the herd of Mr. G. Satterthwaite, who likewise lost two cows, and had two cows and a calf sick at the time of sending for him. PNEUMONIA. There are two conditions of the lungs known as pneumonia,--one, the inflammatory, and the other, the congestive stage. The former may follow an attack of bronchitis, or it may have a spontaneous origin. The congestive is generally the result of cold suddenly applied to an overheated animal, causing a determination of blood to the lungs, which sometimes causes death by suffocation. _Symptoms._--The disease is preceded by a shivering fit; dry skin; staring coat; clammy mouth; short cough; Schneiderian membrane (of the nose) very much reddened; respiration hurried or laborious. In the congestive stage, upon applying the ear to the sides, no sound will be detected; While in the inflammatory stage, a crackling or crepitating sound will be distinctively heard. _Treatment._--In the congestive stage, plenty of pure air will be necessary. Bleed freely; and give in drench one pound of Glauber-salts, with two drachms of Jamaica ginger. Nothing more will be required by way of treatment. In the inflammatory stage, bleeding should seldom be resorted to, except where the animal is in full condition. Apply the following blister to the sides, well rubbed in: oil of turpentine, one ounce; croton-oil, twelve drops; aqua ammonia, half an ounce; linseed-oil, four ounces; mix all together. Give internally one pound of salts in drench, and follow with one of the following powders every four hours: nitrate of potash, one ounce; tartrate of antimony and pulverized digitalis leaves, of each, one drachm; mix all together, and divide into eight powders. Or the following may be given with equal advantage: nitrate of potash, one and a half ounces; nitrate of soda, six ounces; mix, and divide into six powders; one to be given in wash or gruel every six hours. PROTRUSION OF THE BLADDER. This sometimes occurs during the throes in difficult cases of parturition in cows, and the aid of a skillful veterinary surgeon is requisite to replace the inverted bladder. PUERPERAL FEVER.