154 DYNAMICS OF LIVING MATTER 



a capillary tube which was sealed at one end, and then putting the tube 

 with the open end into the water which contained the spermatozoa. 

 "When the liquid in the tube contains only o.oi per cent malic acid, 

 the spermatozoa (of ferns) very soon move toward the opening of the 

 capillary tube. At the same time many spermatozoa move into the 

 capillary tube and within from five to ten minutes many hundreds of 

 spermatozoa may accumulate in the tube. The malic acid acts as 

 well in the form of a free acid as in the form of salts, and that it is a 

 specific stimulant may be seen from the fact that in the same time prob- 

 ably not a single spermatozoon enters a capillary tube containing pure 

 water or a solution of other substances." Massart and Bordet used 

 this method of Pfeffer's on leucocytes.* It had been known for a long 

 time that in inflamed tissues the number of leucocytes increases, and 

 it was generally admitted that at least part of the supemumerous leu- 

 cocytes migrate there from the capillaries. In order to answer the 

 question as to what causes this migration, Massart and Bordet put 

 capillary tubes containing cultures of bacteria, especially staphylo- 

 coccus pyog. aureus into the abdominal cavity of the frog. After twenty- 

 four hours the authors found leucocytes in large numbers in the tube. 

 If a sterile culture medium was introduced, no leucocytes migrated into 

 it. This seems to indicate that substances produced by' the bacteria 

 determine the direction in which the leucocytes move. 



To give a more distinct picture of these phenomena I may mention 

 a few of the observations made by Garrey f on this subject. A small 

 square trough contained the organisms — in this case Chilomonas, an 

 Infusorian. At one side a small capillary tube was inserted, into which 

 the solution of the substance was put whose efficiency was to be tested. 

 At the beginning of the experiment the organisms were equally distrib- 

 uted all over the square space. When very dilute IjCl was put into 

 the capillary tube, a clear circular area entirely free of organisms was 

 soon formed around the opening pf the tube. The organisms recede 

 from the HCl, diffusing into the trough, and thus indicate very nicely 

 the rapidity and extent of diffusion. This clear area increases until 

 the HCl has diffused to the end of the square space, when the organ- 

 isms are again distributed equally. In this case we are probably not 

 dealing with a real tropism, but with a reaction to sudden changes 

 in the intensity of the stimulus. When the organisms go from neutral 

 water to sufficiently acidulated water, they are repelled. According 

 to Jennings, they swim first backward and then toward one side, a 



* Massart and Bordet, Soc. Roy, dts Sciences med. ei nat. de Bruxelles, 3 Fevr., 1890. 

 Reviewed Physiol. Centralblatt, Vol. 4, p. 332, 1891. 



t Garrey, Am. four. Physiology, Vol. 3, p. 291, 1900. 



