122 CHEMISTRY OF BACTERIA AND THEIR PRODUCTS 



a fermentoid. Enzymes as well as toxins are poisonous when injected 

 into animals, and the animals react to each by producing substances 

 (antibodies) that render each inert, probably in the same way. On 

 the other hand, enzymes and toxins seem to produce their effects ac- 

 cording to different laws: — A small amount of enzyme can in course 

 of time produce an almost indefinite amount of effect, whereas toxins 

 act more nearly quantitatively. It seems as if the enzyme were bound 

 to the body upon which it acts, as is the toxin, but that after it has 

 destroyed this body it is set free in a still active form, ready to accom- 

 plish further work, whereas the toxin is either not set free, or it be- 

 comes inactive after it has once bepn combined. 



Agencies Destroying or Modifying Toxins. — Toxins are very sus- 

 ceptible to light, direct sunlight soon destroying the power of toxin 

 solutions. Fluorescent substances destroy toxins both in vitro and 

 in the body.'*^ They are generally destroyed by moist heat of 80°, but 

 resist 100° when dry. Oxygen, even dilute as in air, is harmful; and all 

 oxidizing agents, including oxidizing enzymes, destroy them quicld3^■*- 

 Like enzymes, they withstand such antiseptics as chloroform, tol- 

 uene, etc., and are precipitated by the heavy metals. Some agencies 

 seem to attack only the toxophore portion of the molecule, e. g., iodin, 

 carbon disulphid (Ehrlich). Certain toxins (diphtheria, dysentery) 

 can be converted into non-toxic modifications by acids, the original 

 toxicity being restored by bases (Docrr),''^ which fact, Pick maintains, 

 is in support of the protein nature of toxins. Salts of monovalent 

 metals have no effect on toxins, but bivalent and trivalent salts are 

 injurious to them, tetanus toxin being more sensitive than diphtheria 

 toxin. X-rays are said to weaken them.^'* 



'Introduced into the gastro-intestinal tract, most bacterial toxins 

 are not absorbed (botulinus toxin excepted), cause no symptoms, and 

 do not reappear in the feces; they are therefore destroyed by the 

 contents of the tract, pepsin, pancreatic juice, and bile all being capa- 

 ble of destroying toxins. ^^ They maj% however, when injected sub- 

 cutaneously, circulate unimpaired in the blood of non-susceptible 

 animals, gradually disappearing, more through slow processes of de- 

 struction than by elimination. When injected into susceptible animals, 

 they soon disappear from the blood, being fixed in the organs that 

 they attack. Toxins are also bound ])y lipoids, fats and similar 

 substances, which accounts, at least in part, for the affinity of tetanus 



^' Literature Kiven by Not^uchi, Jour. Kxppr. Med., 1900 (S), 263. 



** According!; to Pitini (liiocheni. Zeit., 11)10 (2.')), 257) toxins cause their harm- 

 ful effcot.s 1)V reihiciiiK tlie oxidizing capacity of the tissues. 



<' Wien. klin. Wocli., 1907 (20), T). 



<' (lerlKirtz, Herl. klin. Wocli., 1909 (40), 1800. 



•"' IJuldwin and Levone (.lour. Mi-d. lie.soarch, 1901 (()), 120) found that diph- 

 tlioria ami tetanus toxin are l)otli destroyed, ai)parently througli digestion, by 

 pci)sin, trypsin and jiajiain acting for several days. Ueview of Literature by 

 Lust, Ifofnieister's lieitr., 1901 (ii), 132. See Vincent, Ann. Inst. Pasteur, 1908 

 (22), 341. 



