Occurrence. Etiology. 367 



quarter of the year. In tlie French Army in the years 1906 and 1901, 18,105 cases 

 with 283 deaths occurred among about 100,000 horses. 



Etiology. Streptococci (Streptococcus eqiii Scliiitz) are in- 

 variably present in the lymph glands and in the nasal discharge 

 of affected horses, formed by cocci arranged in the manner of 

 a string of pearls; these are not always uniform in size and 

 are frequently split transversely. The rounded chains consist 

 of 50 to 60, and even more segments, but much shorter chains, 

 and also diplococci and single cocci may occur. They stain well 

 with aqueous aniline dyes, as well as by Gram's method (Fig. 

 61). 



Cultivation. The streptococcus equi may be cultivated aerobically 

 and anaerobically, at room as well as ])ody temperature. On gelatin 

 very fine white points develop along' the 

 inoculation streak, on agar the colonies 

 have hardly the size of a poppy seed ; they 

 are grayish-white, not transparent, not 

 coalescing, and closely adhering to the 

 medium. On coagulated blood serum 

 glassy transparent, yellowish-gray droplets 

 develop, which later may coalesce forming 

 a tenacious layer. In the water of con- 

 densation a fine precipitation results, 

 which consists of very long chains. In 

 bouillon the organisms grow in fine flakes, 

 which accumulate on the bottom of the 

 tube and over which the fluid remains 



clear; the growth is favored by the addi- Fig. 61. Streptococcus equi. 



tion of blood serum. No growth results on P"s from gland ; fuchsin stain- 

 potatoes. Milk is coagulated; dextrose is "^°' 

 not fermented. 



The relation of streptococci from different derivations to each other has not 

 yet been sufficiently established. While Schiitz considers his streptococcus as an 

 independent species, Foth believed it identical with Schiitz 's diplococcus -of influenza, 

 and also with the streptococcus piyogenus of man. Lignieres considers the identity 

 of streptococcus of strangles and that of influenza proven beyond a doubt, while 

 he believes that Rosenbach's pyogenic streptococcus, which among other diseases 

 plays a part in purjjura hemorrhagica of horses, is an independent species. This 

 conception is supported also by the experience that blood serum from animals immu- 

 nized with 1 of the 2 above mentioned streptococci immunizes only against the respec- 

 tive varieties (Lignieres), and the serum from a horse treated with the strepto- 

 coccus of strangles agglutinates this streptococcus in the proportion of 1:100, while 

 other pyogenic streptococci from animals are agglutinated only at 1:25, and the 

 human, on the other hand, have only a very slight or no agglutinating powers (Pior- 

 kowski). Similar results were also observed by Angelici. He found that the serum 

 of a horse hyper-immunized with strangles streptococci had an agglutinating value 

 of 1:10000-20000, whereas streptococci cultivated from wounds and intestinal eon- 

 tents agglutinated in much lower dilutions. Marmorek considers the two forms of 

 streptococci as not identical, based on his observation that horse streptococci thrive 

 in filtrates of cultures of the streptococcus of man. Besides this Ludwig found some 

 differences in inoculation of cultures on Loflfler's serum, which were manifested by 

 the fact that the streptococcus of strangles produced larger colonies than the 

 streptococcus of man, or the streptococcus of mastoitidis. The identity of the 

 streptococci of different origin is still an unsettled question, the solution of which 

 is surrounded by great difficulties inasmuch as in animal experiments one and the 

 same streptococcus may produce various disease processes (erysipelas, suppuration). 



Baruchello found" streptococci 92 times in 97 samples of feces from 87 horses, 



