as turpentine and oil of mustard, in the absenco of bacteria,* Into tho 

 abdominal lymph apnces of frogs thoy introduced capillary tubefi, closed 

 at ono end, and tilled with the substance whose action was to be examined. 

 They employed f )r their observations cultures of staphylococciis pyogenes 

 albus, and of tho bacilli of fowl cholera, enteric fever, anthrax, etc., and 

 at tho end of twenty-four hours they found tiiat musses of leucocytes had 

 entered tho tubes. Cultures of the staphylococcus were pre-eminent in 

 attructinfi; the leucocytes ; tho j)ure nutrient media, on the other hand, 

 had comparatively little attractive power ; hence it is the bacteria or 

 their products which call into play a positive chemintaxis. That it is tho 

 soluble products was shown by employing the sterilised fluids from which 

 tho microbes had been removed by filtration. Thus Massnrt and Bordet 

 concluded that the products of bacterial metabolism attract leucocytes 

 towards the focus of infection. They further discovered that chloroform 

 and chloral hydrate temporarily suspend the movement of the wandering 

 cells towards tubes containing positively chemiotactic me<lia. 



Ti»e work of these two observers has been extended by wtiiers, notably 

 by Gabritchevskijf working under Metchnikoff. The effects of various 

 substances was determined upon frogs and rabbits, fine glass tubes being 

 placed under tho skin of the first, and in the tissue of the ear of tho other 

 animals. These were extracted in twenty-four hours or less, their con- 

 tents driven out on to a slide, a little weak metliylene blue added, and 

 thus the number of contained leucocytes could be approximately deter- 

 mined. Gabritchevski found that bacteria and their sterilised products 

 set up an equally active positive chemiotaxis, while tubes containing 

 other substances attracted comparatively few leucocytes. An exception 

 to this rule was found in the case of the macerated rabbit's spleen, which, 

 in the rabbit, exerted intense positive chemiotaxis — a fact of some small 

 interest in connection with the bactericidal properties of the spleen, and 

 with Hankin's observations upon the p.irt which splenic extract can play 

 under certain conditions in the prevention of disease. | Neitlier the 

 mechanical irritation induced by the presence of the tubes nor the varying 

 concentration of the contents can suffice to explain the great differences 

 observed. The former varied but little, and with regard to the latter 

 Gabritchevski noted that ten per cent solutions of various salts, which 

 must necessarily have induced much more active diffusion currents than 

 the broth serving as culture medium for the bacteria, brought about a 

 negative chemiotaxis, with paucity of leucocytic tube contents. Chemio- 



* Indeed tho conrticting results gained by various observers In tlii ■nnection are now expli- 

 cable when we know that a given substance exerts a positive cheni xls In one animal — the 

 dog, for instance— so leading to an Inflammation rich In leut^-oytes, u negative chemiotaxis in 

 another— as for example, the rabbit— there producing but a serous inflammation. 



t Gabritchevski. " Sur les propriiites chlmlotactiques des leucocytes."— ^ii/iate <ie I'lnititut 

 Pasteur, IV., 1890, p. 346. 



} Hankin. British Mimical Journal, July 12th, 1890. 



