THE ADRENALS AND BUCHNER'S ALEXINS. 629 



Bucliner is the main exponent. According to this investigator, 

 the blood-serum and body-fluids kill bacteria because they con- 

 tain substances termed "alexins," which are thought to repre- 

 sent the secretory products of leucocytes. The effects of these 

 alexins were found to vary greatly: under certain conditions 

 they can overcome myriads of bacteria in a short time; under 

 others their influence becomes practically nil. The loss of cer- 

 tain salts, for example, deprives them of their bactericidal prop- 

 erty. This also occurs when they are diluted in ten times their 

 volume of water, or when exposed at least thirty minutes to a 

 temperature of 55 C. The addition of certain alkalies, how- 

 ever, enables them to preserve their properties up to 70 C. 

 On the other hand, a brief exposure to the normal body-tem- 

 perature, 37 C., causes them to become somewhat attenuated. 

 More recently Laschtscenko, 18 working in Buchner's laboratory, 

 found it possible to extract the bactericidal alexins from the 

 leucocytes of rabbits without destroying these cells. It is evi- 

 dent, therefore, that, while leucocytes may act as phagocytes, 

 they may also, while living, secrete a bactericidal substance. 

 Metchnikoff's doctrine in respect to phagocytosis proper, and 

 Pfeiffer's doctrine as regards the bactericidal powers of body- 

 fluids, are thereby sustained, but with limitations, since it is 

 clear that phagocytes are not mere scavengers and that they 

 need not die to become poisonous to pathogenic germs. In 

 fact, everything goes to prove that the phagocytic action and 

 the alexinic destructive processes are carried on simultaneously: 

 i.e., that the alexins given out by the leucocytes first weaken the 

 bacteria, and that the latter are then ingulfed, alive or dead, ~by 

 the phagocytes. 



As to the nature of the bactericidal substance, Buchner 

 believes it to be a ferment capable of splitting proteids, and 

 that it submits the bacteria to a process of digestion resembling, 

 to a degree, the effect of blood-serum upon the albuminous 

 constituents of blood-corpuscles. 



If to the protective role of phagocytes in the system we 

 now add alexins or substances secreted by each leucocyte and 

 capable of weakening or killing bacteria, the protective role as 



18 Laschtscenko: "Transactions of the Thirteenth International Congress," 

 1900. 



