Bacteriolytic Element found in Tissues and Secretions. 309 



Lytic Action. . 



Naked-eye Changes, — In the second of the preliminary experiments, it was 

 shown that, if a drop of nasal mucus be added to a thick suspension of the 

 Micrococcus lysodeikticus in a test-tube, there is, after a short period of incuba- 

 tion, a complete clearing of the opaque suspension, so that the fluid becomes 

 perfectly clear to the naked eye. It has been noted also that other tissues 

 and secretions have the same action. If the material used is rich in 

 lysozynie, the action is a very rapid one. Thus, at a temperature of 45° C, 

 a 1 in 100 dilution of tears will completely clear the suspension in about 

 30 seconds, or a 1 in 5 dilution of egg white in 10 seconds. 



If the bacterial suspension is a very thick one, there is easily to be 

 observed a considerable increase in the viscosity of the fluid after lysis of 

 the bacteria has been completed, evidenced by the fact that, if the tube is 

 shaken, the air bubbles rise much more slowly to the surface of the fluid. 



The lytic action can be strikingly demonstrated by placing on the surface 

 of a fully-grown plate culture of M. lysodeikticus a drop of tears, nasal 

 mucus, or other material rich in lysozynie. In less than 1 minute at 37° C, 

 or in about 10 minutes at room temperature, that portion of the culture on 

 which the material was placed will have been completely dissolved, pro- 

 ducing a clear space just as if a portion of the culture had been mechanically 

 removed. 



Microscopic Changes. — When a mixture . of tears and M. lysodeikticus is 

 observed with dark ground illumination, it is seen that the cocci rapidly lose 

 their sharp outlines, become swollen and gradually disappear. At the same 

 time, there appear a very large number of minute granules, somewhat 

 similar in appearance to the granules of a polynuclear leucocyte. 



Examined with transmitted light, it is seen that the cocci rapidly swell up 

 and become transparent, so that, after 2 minutes at room temperature (when 

 the cocci are suspended in undiluted tears), they become quite invisible. 



When the partially dissolved cocci are examined by Burri's method, they 

 are found to be much swollen up, and they are less indistinct, probably 

 owing to some of the opaque material used to produce the dark background 

 adhering to their glutinous surface (see fig. 3). 



If a similar specimen is coloured with one of the ordinary bacterial 

 stains, the stainable material is found to have diminished in size, giving 

 the appearance of small and very irregular cocci. When the lytic action is 

 complete, staining fails to reveal any trace of the cocci. 



