'SO 6 



Mr. A. Fleming. On a Remarkable 



mechanical effect., its velocity depending on the extensibility of the vessels 

 as modified by any condition (muscular or otherwise) obtaining at the 

 moment. 



REFERENCES. 



(1) ' Hermann's Handbuch,' vol. 4, p. 229 (1880). 



(2) Rhode, 'Arch. f. exp. Path.,' vol. 68, p. 401 (1912). 



(3) Roy, ' J. Physiol.,' vol. 3, p. 125 (1880). 



(4) Luciani, ' Human Physiology,' vol. 1, pp. 261-263 (1911). Macmillan. 



(5) Gallavardiu, ' La Tension arterielle en Clinique,' Paris, 1920, p. 169. Massou. 



(6) Morrow, ' Pfliiger's A.rch.,' vol. 79, p. 442 (1900). 



(7) Moens, ' Die Pulskurve,' Leiden, 1878, p. .90. 



On a Remarkable Bacteriolytic Element found in Tissues and 



Secretions. 

 By Alexander Fleming, M.B., F.K.C.S. 



(Communicated by Sir Almroth Wright, F.B.S. Eeceived February 13, 1922.) 

 (From the Laboratory of the Inoculation Department, St. Mary's Hospital.) 



[Plate 9.] 



In this communication I wish to draw attention to a substance present 

 in the tissues and secretions of the body, which is capable of rapidly 

 dissolving certain' bacteria. .As this substance has properties akin to those 

 of ferments I have called it a " Lysozyme," and shall refer to it by this 

 name throughout the communication. 



The lysozyme was first noticed during some investigations made on a 

 patient suffering from acute coryza. The nasal secretion of this patient was 

 cultivated daily on blood agar plates, and for the first three days of the 

 infection there was no growth, with the exception of an occasional staphy- 

 lococcus colony. The culture made from the nasal mucus on the fourth day 

 showed in 24 hours a large number of small colonies which, on examination, 

 proved to be large gram-positive cocci arranged irregularly but with a 

 tendency to diplococcal and tetrad formation. It is necessary to give here a 

 very brief description of this microbe as with it most of the experiments 

 described below were done, and it was with it that the phenomena to be 

 described were best manifested. The microbe has not been exactly identified, 

 but for purposes of this communication it may be alluded to as the Micrococcus 

 lysodeikticus. 



