On Blood-Platelets. 



465 



tion with Dr. W. E. Gye. Cramer and Gye (3) found that the injection of 

 calcium salts, colloidal silicic acid and other colloids and even distilled water 

 produced at the site of injection a diminution in the resistance to infection. 

 They showed subsequently (4) that all these different substances have in 

 common that they produce the same lesion : a damage to the endothelium of 

 the smaller blood-vessels which elicits an agglutination of the platelets 

 within the vessel, and the formation of a white thrombus with a resulting 

 local disturbance in the circulation (see Plate VI, fig. 3, in VI. Scientific Report 

 •of Imperial Cancer Eesearch Fund). At the same time lymph and plasma 

 pass out into the surrounding connective tissue where they form a gelatinous 

 clot. When the washed bacteria of gas gangrene or tetanus are injected at 

 the site of this lesion the specific disease (gas gangrene or tetanus as the case 

 may be) is elicited in a very virulent form at this site. The same bacteria 

 when injected into a different site of the same animal do not elicit the disease 

 there but, as in a normal animal, undergo phagocytosis and lysis. At the site 

 of the lesion active phagocytosis is still proceeding, but evidence of lysis has 

 never been observed. This phenomenon of defence rupture is not restricted 

 to the anaerobic bacteria of gas gangrene and tetanus, but holds good also for 

 streptococci, and has recently been shown by Gye and Kettle to be valid also 

 for tubercle bacilli. The lesion responsible for this phenomenon is one which 

 puts the platelets " out of commission," so to speak, locally by agglutinating 

 them, and which, by its interference with the circulation, prevents the access 

 ■of new platelets. This leads to a local diminution in the resistance to 

 infection. In the thrombopenia of vitamin A deficiency, or after exposure 

 to radium, there is a general absence of platelets, and this leads to a general 

 diminution in the resistance to infection. 



The literature contains some statements which afford direct evidence that 

 the platelets are concerned in the elaboration of bactericidal substances. The 

 washed platelets and leucocytes do not contain any bactericidal substances 

 when tested against the anthrax bacillus. But when they are mixed with 

 tissue fluids which, by themselves, are inactive, they confer upon this fluid an 

 intense bactericidal power (Gruber and Futaki (5)). It should be noted that 

 these bactericidal substances are not identical with the hemolytic complement. 



More recent work would appear to assign to the platelets a somewhat 

 different function. C. G. Bull (6) has shown in a series of papers that 

 certain bacteria (staphylococci, colon bacilli, meningococci, typhoid bacilli, 

 non-virulent pneumococci and non-virulent influenza bacilli) are rapidly 

 agglutinated when injected into the blood of a normal rabbit or dog. 

 This is followed by a rapid removal of the bacteria from the circulation 

 and by phagocytosis and destruction of the agglutinated bacteria in the 



vol. xciii. — b. 2 L 



