1905.] On Spontaneous and other Phagocytosis. 213 



This appellation may, we think, be characterised as unfortunate, first, 

 because the mode of action of the incitor element was prejudged ; secondly, 

 because the appellation suggests (in contravention to everything which has 

 come to light with respect to immunisation) that there are elaborated in the 

 animal organism in response to inoculations, not vaccinotropic elements 

 (elements which have a chemical affinity for the vaccine) but leucocytropic 

 elements (substances which have a chemical action on leucocytes). 



At a later date the terms " sensitiser " and " fixing substance " {la substance 

 sensibilitrice and le fixatcur) were applied by Metchnikoff to the incitor 

 element. This nomenclature is, it seems to us, almost equally infelicitous — 

 infelicitous because it imposes upon the mind the following ideas : — («) that 

 the phenomena of phagocytosis are analogous to those of haemolysis ; 



(b) that the incitor substance, like the " amboceptor " of Ehrlich, exerts its 

 specific effect only in the case where it is reinforced by a complement ; and 



(c) that the mechanical movements of the phagocyte in the ingestion of 

 particulate matter are analogous to the chemical action of the complement in 

 the case where red blood corpuscles are dissolved by a hemolytic serum. 



With the exception of Leishman,* who, with a view to conforming to the 

 original nomenclature of Metchnikoff, and also because his own experi- 

 ments incline him to adopt the same point of view, speaks of the incitor 

 substances as stimulins, all the other observers! take the view that the 



the leucocytes was first inquired into by Denys and Leclef ('La Cellule,' 1895, vol. 11), in 

 connection with their experiments conducted on rabbits with streptococcus. The doubt 

 with regard to the correctness of Metchnikoff's view which found expression in the 

 paper of these authors was further justified by the experiments of Mennes (' Zeitsch. f. 

 Hygiene,' 1897, vol. 25), conducted with the blood of animals immunised against the 

 pneumococcus. Finally, the incorrectness of the view that immunisation depends on a 

 modification of the leucocytes was for the first time unambiguously established by one of 

 us working in conjunction with Douglas (' Roy. Soc. Proc.,' vol. 72, p. 369, and vol. 73 

 p. 129). Our results were afterwards confirmed by Bulloch (' Roy. Soc. Proc.,' vol. 75). 

 * Loc. cit. and ' Journ. of Hygiene,' 1895. 



t It may be remarked in this connection that Neufeld and Rinipau, while satisfied that 

 the incitor substances in the serum exert an opsonic action on the bacteria, suggest that 

 the term opsonins should be here rejected and that the substances here in question 

 should be called bacteriotropras. Pending the discussion of the questions of the mode 

 of action of the incitor elements in the heated serum, and of their identity or non- 

 identity with the opsonins found in normal blood, it will suffice here to remark with 

 respect to the proposed nomenclature of Neufeld the following : — 



(«) The term bacteriotropins (since it connotes nothing move than the property of 

 entering into chemical combination with bacteria) is more appropriate as a generic term 

 for the whole class of substances which combine chemically with bacteria, than as a 

 specific designation for the substances which prepare the bacteria for phagocytosis. 



(b) All considerations of the comparative merits of 2seufeld's terminology and my 

 terminology apart— there must, I apprehend, remain to me as the author of the term 

 VOL. LXXV1I. — I!. Q 



