On Spontaneous and other Phagocytosis. 211 



In contrast with the observations incorporated in Table II in the body of 

 the paper these observations were conducted in phagocytic mixtures 

 containing 085 per cent, instead of PI per cent, of NaCl. It is shown 

 in the next following communication that spontaneous phagocytosis is 

 absolutely abolished only in the case when the salt content of the phagocytic 

 mixture exceeds 1 per cent. 



The source of fallacy to which attention is here called falls, no doubt, for 

 all practical purposes, entirely out of account. 



On Spontaneous Phagocytosis, and on the Phagocytosis which is 

 Obtained ivith the Heated Serum of Patients who have 

 Responded to Tubercular Infection, or, as the case may be, to 

 the Inoculation of a Tubercle Vaccine. 



By A. E. Wright, M.D., sometime Professor of Pathology, Army Medical 

 School, Netley, Pathologist to St. Mary's Hospital, London, W., and 

 Staff-Surgeon S. T. Eeid, E.N. 



(From the Pathological Laboratory of St. Mary's Hospital, London, W.). 



(Communicated by Sir John Burdon-Sanderson, Bart., F.R.S. Received 

 October 21,— Bead November 23, 1905.) 



It has been indicated in the foregoing paper than an incitor element* is to 

 be found in the blood of those who have made an immunising response to 

 tubercular infection, or, as the case may be, to an inoculation of a tubercle 

 vaccine. This fact does not stand by itself. 



Recital of Previous Observations on the same Subject. 



The observations of Metchnikoff, following in sequence upon the classical 

 researches of B. Pfeiffer on the intraperitoneal destruction of bacteria by the 

 aid of immune sera, first drew attention to the fact that very active phagocy- 

 tosis comes under observation when bacterial cultures, or as the case may be 

 spermatozoa, are introduced into the peritoneal cavity of normal animals in 

 association with heated serum derived from immunised animals. 



* The term " incitor-element " (Latin — incito : I hasten, I urge forward, I bring into 

 rapid movement) is here employed to denote the element in the heated serum which 

 promotes phagocytosis. By employing this term, pending the elucidation of the nature 

 and mode of action of the element in question, we secure the advantage of leaving these 

 issues unprejudged. 



