PHAGOCYTOSIS 2QI 



and the best is, perhaps, that given by Bassett-Smith, who found 

 that in Malta fever the patient's leucocytes may be decidedly 

 more potent than normal ones, when used in conjunction with 

 the patient's serum, though, when normal serum is used, the 



difference may disappear. Thus : 



Cocci per Leucocytes. 



Patient's serum + patient's leucocytes + emulsion of cocci 23-0 46' 



+ normal leucocytes + ,, ,, 8'6 25-0 



Normal serum + patient's leucocytes + ,, ,, i6'o 30*0 



,, ,, + normal leucocytes + ,, ,, 19*0 2Q'o 



Rosenau has also brought forward evidence to show that 

 leucocytes from cases of pneumonia have greater phagocytic 

 powers than those from healthy persons, and are less easily 

 killed by heat. 



Much attention was attracted of late by Bail's theory of the 

 aggressins. Bail found that if washed tubercle bacilli were injected 

 in large amount into the peritoneum of guinea-pigs infected with 

 tubercle, the animals died rapidly i.e., in eight hours or so. 1 

 There was a fluid exudate (containing lymphocytes) in the peri- 

 toneal cavity, and this exudate (centrifugalized to get rid of cells 

 and bacteria) was found to have a remarkable action in increasing 

 the virulence of young tubercle bacilli to normal animals. Thus, if 

 a few cubic centimetres were injected together with the bacilli, 

 death occurred in about twenty hours, instead of in some weeks. 

 He found that this virulence was apparently due to an inhibitory 

 effect which the fluid exerted on phagocytosis. When bacilli 

 were injected into a normal animal without the exudate, many 

 polynuclears appeared in the peritoneal fluid and many large 

 mononuclear cells, and many of the bacilli were taken up ; but 

 when bacilli and exudate were injected, few cells other than 

 lymphocytes were seen, and there was no phagocytosis. 



These observations were confirmed and extended by Bail and 

 others, and similar phenomena were found to occur in the case of 

 numerous other organisms, if not in all. A very striking example 

 was given by Weil in the case of the bacillus of chicken cholera, 

 which is extremely virulent to rabbits, so that a millionth of a 

 culture (containing perhaps but one bacillus) is certainly fatal. 

 A minute trace was injected into the pleura, and the animal died 

 in a few hours. Several cubic centimetres of turbid exudate, the 



1 This, of course, is equivalent to the tuberculin reaction in an extreme 

 form. 



192 



