790 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
tlie following facts as proving that there was some connection between the 
immunity of a given animal against a given infectious disease, and 
the bactericidal action of its blood on the micro-organism producing the 
disease : — 
(а) The blood and serum of animals, such as mice and guinea-pigs, 
which readily succumbed to anthrax, had no bactericidal power on 
anthrax-bacilli. 
(б) The serum of animals which took anthrax readily never possessed 
such a strong bactericidal action as the serum of white rats, which were 
immune against anthrax. 
(c) The blood and serum of animals rendered artificially immune 
possessed stronger bactericidal powers than the blood and serum of 
normal animals. 
( d ) The blood and serum of animals rendered artificially immune 
against a given micro-organism lessened the virulence of the specific 
micro-organism causing the disease. 
(e) Whenever blood and serum possessed no bactericidal action on 
micro-organisms, this absence of bactericidal action might be due to the 
fact that, owing to the necessary manipulations, this bactericidal sub- 
stance had been altered or even destroyed. 
As further proving that the immunity of animals depended on some 
substance present in the serum, he mentioned the facts described by 
Behring, Kitasato, Ogata, and Emmerich, in which the injection of 
blood or serum of an animal immune against a given bacillus, cured 
another animal afflicted with the same disease. The curative power he 
attributed to the presence in the blood of immune animals of a protective 
substance, probably proteid in its nature, to which he gave the name of 
“ alexine ” (from aXe^etv, to protect). These alexines were not ordi- 
nary oxidation products of the tissues, as they were quite specific in 
their action. They were not simply enzymes, as they had no hydrolytic 
properties, but they were most probably proteid substances. These 
alexines were probably formed in the cells ; but, when formed, their 
action was quite independent from that of cells, and they were probably 
always present in immune animals. 
Mr. E. H. Hankin said that theoretical considerations led him to 
suspect that a particular ferment-like proteid, known as cell-globulin B, 
was a substance possessing bactericidal power. He tested its action 
on anthrax bacilli, and found that it had the power of destroying these 
microbes. He further found that similar substances were present, not only 
in animals that were naturally immune against anthrax, but also in those 
that were susceptible to this disease. To these substances he had given 
the name of defensive proteids. In his published papers on this sub- 
ject he had noted various similarities in the bactericidal action of these 
substances, and that possessed by blood-serum, and these resemblances 
were such as to leave little room for doubt that the bactericidal action 
of blood-serum was due to the presence of these defensive proteids. 
The serum of white rats contained a proteid body possessing a well- 
marked alkaline reaction, and a power of destroying anthrax bacilli. 
Further, when injected into mice along with fully virulent anthrax spores, 
it would prevent the development of the disease. On the other hand, 
defensive proteids of animals susceptible to anthrax did not exert such 
