220 CHEMISTRY OF THE IMMUNITY REACTIONS 



able, because it has been described as resisting heat above the boil- 

 ing-point, and Jordan'^^ seems to have proved that the hemolysis is 

 ascribable to the alkalinity that this organism produces in culture- 

 media. Other bacterial hemolysins are, however, destroyed by heat 

 at 70° or less for two hours; but they are altogether different from 

 ordinary immune hemolysins. Apparently streptocolysin is simph' a 

 toxin for red cel,ls,^^ and unites directly to the cell receptois without 

 the intervention of any intermediary body. As a similar structure has 

 been shown for staphylolysin and tetanolysin, it is probable that the 

 bacterial hemolysins are all merely toxins with a particular affinity for 

 red cells, and against some of these bacterial hemotoxins antitoxic sera 

 are obtainable, although there is usually some question as to how much 

 of the antagonistic effect depends on true antitoxins and how much 

 upon the cholesterol in the serum. However, a- strong antiserum has 

 been obtained against the hemotoxin of B. Welchii.^^ Of course 

 bacteria may also form many non-specific hemolytic substances as 

 products of their metabolism, such as acids and bases. 



Secondary anemia occurring in the infectious diseases is probably 

 to be explained largely by this hemol3^tic property of bacterial toxins. 

 Hemoglobinuria may also be produced in the same way in some in- 

 stances. Intravenous injections of filtrates of the saprophyte, B. 

 megatherium, will produce hemoglobinuria in guinea-pigs, hence hemo- 

 lysis is not an exclusive property of pathogenic bacteria, and with 

 streptococci LyalP^ found that the hemolysin titer did not afford a 

 criterion of virulence. No immunity to streptococci is produced in 

 animals immunized with streptococcus hemolysin.^- Pneumococci 

 produce an intracellular hemolytic toxin which is very labile and 

 antigenic; living pneumococci convert hemoglobin into methemoglobin, 

 but this the hemolytic extracts of pneumococci cannot do (Cole).^^ 

 Streptococcus viridans has the same propertj^,^* which may play a 

 part in the effects of infections with these organisms, von Hellens^* 

 states that streptocolysin is ether soluble and heat resistant. 



Hemolysis by Vegetable Poisons 



A number of plant poisons are strongly homolj'tic, and some of 

 them owe much of their to.xicity to their effect on the erj'throcytes. 

 One group consists of the bodies often called "vegetable toxalbu- 

 mins," because they seem to be proteins, and includes ricin, abrin, 

 crotin, curcin and robin. ^^ Of these, crotin and curcin are particu- 



«8 Jour. Medical Research, 1903 (10), 31. 



«9 Jour. Amer. Med. Assoc, 1903 (41), 962; Jour. Infect. Dis., 1907 (4), 277. 

 s" Ford and Williams, Jour. Immunol., 1919 (4), 385. 

 »' Jour. Med. Kes., 1914 (30), 515. 



»2 McLcod and McXeo, .lour. Path, and Bact., 1913 (17), 524. 

 »3 Jour. J']xper. Med., 1914 (20), 347, 3ti3. 

 »' liiakc, Jour. Expcr. Mod., 1910 (24), 315. 

 . »" Cent. f. Bakt., 1913 ((iS), 002. 



^^ The sap of (Cotyledon Schcidcckeri contains hemolytic substances of peculiar 

 character. (See Kritchevvski, Jour. Exp. Med., 1917 (20), 069.) 



