Bacteriolytic Element found in Tissues and Secretions. 307 



The fully developed colony of the coccus may be 2 or 3 mm. in diameter ; 

 it is round, opaque, raised, and has a bright lemon yellow colour ; it grows 

 luxuriantly on all the ordinary culture media, and growth takes place well at 

 room temperature, or in the incubator at 37° C. ; it is aerobic and faculta- 

 tively anaerobic ; it does not liquefy gelatin or coagulated albumin. 



Preliminary Experiments Showing the Action of the Lysozyme. 



In the first experiment nasal mucus from the patient, with coryza, was 

 shaken up with five times its volume of normal salt solution, and the 

 mixture was centrifuged. A drop of the clear supernatant fluid was placed 

 on an agar plate, which had previously been thickly planted with 

 M. lysodeikticus, and the plate was incubated at 37° C. for 24 hours, when 

 it showed a copious growth of the coccus, except in the region where the 

 nasal mucus had been placed. Here there was complete inhibition of 

 growth, and this inhibition extended for a distance of about 1 cm. beyond 

 the limits of the mucus. 



This striking result led to further investigations, and it was noticed that 

 one drop of the diluted nasal mucus added to 1 c.c. of a thick suspension of 

 the cocci caused their complete disappearance in a few minutes at 37° C. 



These two preliminary experiments clearly demonstrate the very powerful 

 inhibitory and lytic action which the nasal mucus has upon the M. lysodeikticus. 

 It will be shown later that this power is shared by most of the tissues 

 and secretions of the human body, by the tissues of other animals, by vegetable 

 tissues, and, to a very marked degree, by egg white. 



Further Observations on the Effect of the Lysozyme on Bacteria. 



1. Inhibitory Action. 



In the preliminary experiments it has been shown that on the surface of 

 an agar plate the growth of the nasal coccus is completely inhibited by super- 

 added nasal mucus. This inhibitory action can be strikingly demonstrated 

 in another manner. 



A small portion of the agar is removed from an ordinary agar plate making 

 a cup into which some material rich in lysozyme (tears, nasal mucus, sputum, 

 cartilage, egg white, etc.) is placed. A drop of liquid agar, at a temperature 

 of about 50° C, is placed on the material in the cup and is allowed to solidif} T , 

 after which the cup is filled with the liquid agar which, in its turn, is allowed 

 to set. Liquid agar is then poured all over the plate to make a thin layer 

 over the original surface. The whole surface of the medium is now thickly 

 planted with the M. lysodeikticus and the plate is incubated for 24 hours, 

 when it will be seen that there is copious growth of the coccus, except in the 



z 2 



