168 MANUAL OF POISONOUS PLANTS 



Pathogenesis. Infection with this micrococcus causes a marked hyper- 

 leucocytosis. Its presence in tissues is generally followed by the production 

 of pus made up of serum, polymorphonuclear leucocytes, disintegrated tissue, 

 and the bacteria. Ordinarily, the area of infection and inflammation is walled 

 off by an infiltration of the surrounding tissues by these polymorphonuclear leu- 

 cocytes, forming the so-called pyogenic membrane. 



Poisonous properties. In 1894, Van der Velde discovered that sterile fil- 

 trates from cultures of Micrococcus contain an hemolysin, which he termed 

 staphylotoxin. In 1901, Neisser & Wechsberg studied this hemolytic substance 

 and gave to it the name staphylolysin. This substance will cause the erythrocytes 

 to dissolve whether within or without the body. A true toxin, leucocidin, is 



produced under certain conditions. It causes the 

 leucocytes to swell up and their nuclei to disap- 

 pear. Leucocidin and staphylolysin differ from the 

 true toxins in that they are not capable of pro- 

 ducing anti-toxins after having been heated, i. e., 

 toxoids are not formed. T.he normal blood 

 serum, however, of man and animals contains 

 more or less of this anti-toxin. The presence of 

 an endotoxin has not been demonstrated. 



P " Immunity. The resistance of the body may 



Fig. 27. Pus organism (Staphy- b e heightened by immunization with pure cultures 



lococcus pyogenes aureus) shown in , , , ,, , 



irregular bunches. After Fliigge. of the organism. Immunity is undoubtedly due 

 in large part to the phagocytic activity of the leucocytes. It seemed that vir- 

 ulence of the organism has very little relation to the production of toxins by 

 them for some very virulent types produce very small quantities of toxin. There 

 is some substance secreted which is positively chemotactic to the phagocytes. 

 Immunization is not due to the production of bacteriolysins in the blood. Im- 

 mune sera have been produced, but have not proven to be of any practical 

 importance. Vaccination is held by Wright to raise the opsonic index of the 

 blood; to this he attributes increased resistance. Agglutinins are present in 

 normal sera in most cases, but systematic injection greatly increases the ag- 

 glutinating power of the blood. 



Micrococcus caprinus, Mohler and Washburn 



Disease produced. Takosis. 



Animals originally infected. Angora goats. 



Susceptible animals. Mouse, guinea pig, rabbit. 



Animals naturally immune. White and brown rat, chicken, dog, and sheep. 



Pathogenesis. Anatomically characterized by emaciation and anemia, con- 

 gested pneumonic areas in the lung, splenitic atrophy, and induration, spleen 

 often being attached to the diaphragm and neighboring organs by fibrous tissues. 

 The mucous membranes exhibit necrosed areas of mucosa and bacteria are 

 distributed through the blood, consequently may be isolated from any of the 

 internal organs. 



Poisonous properties. Microscopically, the lungs are found with many of 

 the terminal bronchioles and alveolae filled mucus and desquamated epithelium, 

 in the liver, hyperaemia with fatty degeneration of periphery of many of the 

 acini, catarrhal nephritis, localized areas of parenchymatous degeneration in 



