308 



Mr. A. Fleming. On a Remarkable 



region of the implanted material. By the method of preparation of the plate, 

 in which the material is covered with several distinct layers of agar, there can 

 be no mechanical transference of the material to the surface of the plate, but 

 the experiment shows that the inhibitory substauce is able to penetrate the 

 agar and absolutely prevent growth of the coccus for a distance of about 1 cm. 

 Further, if the plate is kept for a few days, it is found that portions of the 

 growth next to the inhibition zone have become almost transparent, and it is 

 evident that the lytic substance has continued to diffuse through the agar after 

 the microbes have completed their growth, and has dissolved the cocci for a 

 distance of 3 or 4 mm. The area of inhibition and the partially dissolved 

 zone of growth are shown in Plate 9, fig. 1, which is a photograph of a plate 

 in which was imbedded 10 cmm. of tears. 



2. Bactericidal Action. 



If cultures are made from the inhibition zone of a plate, such as has been 

 described in the last experiment, no growth results, showing that the bacteria 

 implanted on this surface has been destroyed. It can also be shown that if 

 lysozyme-containing material be added to a suspension of M. lysodeikticus in a 

 test-tube these cocci are destroyed, so that cultures made from the tube remain 

 sterile. In one experiment a suspension of M. lysodeikticus, of a strength of 

 not less than 1,000 million per cubic centimetre, was exposed to the action of 



1 in 100 nasal mucus and 10 cmm. volumes were planted out after incubation 

 for 1, 2, 5, 10, and 60 minutes. It was found that the cultures remained 

 sterile while similar cultures made at the same time from a control tube in 

 which the nasal mucus was replaced by normal salt solution, gave copious 

 growth up to the end of the experiment, namely, 1 hour's incubation. 



It was found that after 2 hours' incubation tears diluted 9,000 times with 

 normal salt solution killed the whole of the cocci in a thick suspension of the 

 M. lysodeikticus. In the dilutions of tears from 1 in 27,000 to 1 in 243,000 

 there was a very marked bactericidal power manifest. 



The bactericidal action of the lysozyme may also be shown with microbes 

 other than the nasal coccus. An example of this is illustrated in fig. 2, which 

 is a photograph of a culture made after incubating a faecal streptococcus for 



2 hours at 45° C, with tears diluted in 1 in 100 and with normal saline 

 solution. It will be seen that from the saline tube there resulted a continuous 

 sheet of growth, whereas, from the tube containing the tears, there were only 

 scattered colonies, showing that the vast majority of the streptococci had been 

 destroyed by the tears. 



A similar result was obtained by acting on Streptococcus feecaMs with the 

 inflammatory exudation into a joint cavity. 



