taxis — tho attrnction or repulsion of tho wnii(lerii)^ cells — is alono Buffi- 

 ciont to explain the ivsiiltH obtained. And tliis chemiotiixis varies 

 with each apocies. Thus tiiu number of leucocytes entering tho tubes 

 under the sumo conditions is ten times as much in the rabbit an in tho 

 frog, and wherciiH papayotino is indifferent in its manifestation in the 

 latter, it is in the former positively chemiotactic. What is more, indi- 

 viduals of tl»o same species show distinct variations. 



All biictcriii and their products are not positively chemiotactic. For 

 example, it was found that, among those experimented with, the bacillus 

 of fowl cholera led to a negative chemiotaxis (when fresh cultures wore 

 taken), while the observations of others would lend to the belief that 

 Gabritchevsky employed old or attenuated cultures of the staphylococcus 

 pyogenes, for, as he himsdlf (piotes from Steinhaus in another portion of 

 his paper, this microbe inoculated into rabbits ordinarily causes no sup- 

 puration, no collection of leucocytes, but rather a repulsion of tho same, 

 and yet ClabritchevsKy determined that in this animal it produces a 

 distinct positive chemiotaxis.* 



It is unnecessary to give tiio data of other workers in tho same field, 

 for they substantially confirm what has been said above. Enough 

 evidence has been brought forward to show that this attraction or repul- 

 sion of the leucocytes exorcised by tho pathogenic bacteria and their 

 products must be a highly important factor in the prevention or spread 

 of bacterial gi'owth within tho system. 



But whether these chemiotactic phenomena can bear tho weight 

 thrown upon them in Metchnikoff's theory is a matter which I am in- 

 clined to think cannot bo definitely decided until still more work has 

 been accomplished upon tho subject. Undoubtedly, at first siglit, 

 chemiotaxis would seem qualified to elucidate every difliculty of a 

 certain order. It is fitted to explain how it happens that under one 

 set of conditions ample phagocytosis manifests itself, under another, the 

 phagocytes are conspicuous by their absence. Yet it has still to l;e 

 shown that the inception of bacteria by the attracted leucocytes is in 

 direct relation to the force of attraction. It is quite a possible case 

 that the bacterial products may, under special conditions, attract power- 

 fully the wandering cells, and yet that these show little inclination to 

 incept the bacteria, the disease thus extending in spite of the positive 

 chemiotaxis. The validity of this contention is shown by certain 

 observations, as yet unpublished, to which Mr. Hankin very kindly 



• Prom his observations, Gabritchevsky miikcs tho following classification ;— (1) PossesBlng a 

 negative chemiotaxis ; 10 per cent solution of sodium and potassium salts, lactic acid, aIeohol> 

 chloroform (watery solution), jequirity (2 per cent), glycerine, bile, bacillus of fowl cholera. 

 (2) Indifferent, exercising a faint attraction : dlHtilled water, weak solution of sodium and potas- 

 sium salts, carbolic acid, ontlpyrine (1 per cent), phloridzine (1 per cent), glycogen (1 per cent) 

 peptone (1 percent), beef broth, blood, aqueous humour, carmine in siispension. (:!) rossesslng 

 a positive chemiotaxis : sterilised and non-sterilised cultures of pathogenic and non-pathogenic 

 bacteria— staphylococcus, B. pyooyancus, B. anthracis, B. typhoid abd., B. prodigiosus, etc. 



