52 EQUINK PLEURO-PNEUMONIA 



chains. Distinct capsules were not observed. In bouillon 

 cultures, however, they appeared in long chains, leaving the 

 liquid clear, as described by Schiitz. 



This streptococcus did not grow in gelatin, or on serum, 

 or on potato. It would not develop in acid media. On agar 

 the colonies were small and characteristic of streptococci, i. e. , 

 with a thickened, convex, grayish center surrounded by a 

 thin, spreading bluish border, nearly equal in width to the 

 diameter of the central portion. It fermented dextrose, lac- 

 tose and saccharose, with the formation of acids but no gas. 

 Milk remained unchanged in appearance. 



In mice and rabbits, it produced a rapidly fatal septicemia, 

 but guinea-pigs were unaffected. A horse inoculated in the 

 pleural cavity with a small quantity of the culture was killed 

 lo days later. At the point of inoculation and extending over 

 an area equal to one-half of the lung, there were strong adhe- 

 sions between the lung and parietes. The subjacent lung 

 tissue was hepatized. Pure cultures of the streptococcus were 

 obtained from the exudate and from the hepatized lung. 



Although a few discrepancies exist between the descrip- 

 tion of Schiitz' s organism and this streptococcus, in the more 

 essential features they seem to be identical. The cases were 

 examined before the publication of Lignieres' results, and the 

 methods employed did not meet the requirements of those used 

 in isolating his cocco-bacillus. Although a very careful histo- 

 logical study of the pneumonic tissue was made, Ligniere's 

 organism was not detected. It is known that a bacterium, 

 resembling that described by I^ignieres, exists normally in the 

 upper air passages of a certain number of horses. 



The period oj incubation is %\v&n as varying from one to 

 fourteen days, but usually from four to ten days elapse from 

 the time of exposure to the development of the first symptoms. 



§ 34. Symptoms. The symptoms vary to a marked de- 

 gree. When pneumonia develops early in its course, the dis- 

 ease may appear suddenly ; and in addition to the elevation of 

 temperature there is a cough with difficult breathing. Often 



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