VENOMS, TOXINS, ANTIBODIES 363 



affected by ultra-violet light in its hemolytic properties, while M piece, 

 the globulin fraction, is extremely susceptible. Evidently there is 

 associated with the globulin fraction of serum a lytic principle, the true 

 alexin, which may be inactivated by light independently of coagulation 

 of the globulin, but which, nevertheless, cannot cause hemolysis unless 

 the globulin is in a certain very definite state which depends upon pH, 

 salts, other proteins {e.g., E piece and amboceptor), etc. 



The nature of this lysin or alexin proper is still in question, but 

 Noguchi's work (125) on emulsions of soap in protein sols, similar sug- 

 gestive experiments by Schubert (142), and other evidence cited by 

 Brooks (29) lead the writer to the view that the lysin itself probably 

 contains fatty acids, probably unsaturated, either as soaps, lipins, or the 

 like. Irradiation experiments have been of considerable importance 

 in suggesting and supporting such a view. If this hypothesis is correct, 

 the great comparative labiUty of alexin is probably due to the presence 

 of a double bond which is readily oxidized photochemically. 



It should be noted, however, that the prevailing opinion favors the 

 view expressed by Wells (163) that alexin is simply serum proteins, 

 particularly globuUns, in a particular physicochemical and colloidal 

 state. 



Properties Related to Hemolytic Alexin. — Blood serum possesses 

 cytolytic powers affecting cells other than erythrocytes. It has not been 

 shown that such properties are in reality due to the same substance, 

 although that would not appear improbable. Instances of destructive 

 effects of irradiation on cytolytic properties of serum are not numerous. 

 Busck (31) studied the toxicity of serum for paramecia, caUing this 

 property alexin, and found it to be destroyed by midday sunlight when 

 fluorescein dyes, methylene blue, cyanin, or anthracene dyes were mixed 

 with the serum. The same effect could be obtained by using ultra- 

 violet Ught in the absence of dyes. Condensed light from a carbon 

 arc {e.g., 45 volts, 50 amp.) was used, and the inactivation was produced 

 by the Hght which could not pass through glass, hence of wave-length 

 X < 3000 A. 



Eidinow (50) reported that defibrinated blood given ultra-violet 

 irradiation in vitro lost its bactericidal power for Staphylococcus alhus. 

 This loss of bactericidal power may represent alexin destruction. It 

 would probably have been much more rapid if erythrocytes had not been 

 present to absorb so much of the incident light. 



The hemolytic property of the cerebrospinal fluid is apparently quite 

 different from alexin; it is not merely thermostabile at 70°C., but upon 

 ultra-violet irradiation actually increases in amount, even when irradia- 

 tion is carried far enough to make the fluid deep brown in color and to 

 smeU strongly of "burnt skin" (Danielopolu, 40). In the same fluid 

 there is, however, a substance which protects erythrocytes against 



