342 DIPHTHERIA. 



survive for two or three days there is usually albuminuria, 

 and post mortem nephritis is found to be present. 



In the case of the toxine as of the living bacilli, when 

 the animals such as guinea-pigs, rabbits, dogs, etc., survive 

 long enough, paralytic phenomena may occur. The hind 

 limbs are usually affected first, the paralysis afterwards 

 extending to other parts, though sometimes the fore-limbs 

 and neck first show the condition. After paralysis has 

 appeared, a fatal result usually follows in the smaller 

 animals, but in dogs recovery may take place. One point 

 of much interest in relation to the relative nature of toxicity 

 is the high degree of resistance to the toxine possessed by 

 mice and rats. Roux and Yersin, for example, found that 

 2 c.c. of toxine, which was sufficient to kill a rabbit in sixty 

 hours, had no effect on a mouse, whilst of this toxine even 

 Y'TJ- c.c. produced extensive necrosis of the skin of the 

 guinea-pig. 



Properties and Nature of the Toxine. The toxic sub- 

 stance in filtered cultures is a relatively unstable body. 

 When kept in sealed tubes in the absence of light, it pre- 

 serves its powers almost unaltered for several months, but 

 on the other hand, gradually loses them when exposed to 

 the action of light and air. Heating at 58 C. for two 

 hours destroys the toxic properties in great part, but not 

 altogether. When, however, the toxine is evaporated to 

 dryness, it has much greater resistance to heat. One 

 striking fact, discovered by Roux and Yersin, is that after 

 an organic acid, such as tartaric acid, is added to the toxine 

 the toxic property disappears, but that it can be in great part 

 restored by again making the fluid alkaline. 



The toxic body in filtered cultures can be precipitated 

 by alcohol, and is also carried down by calcium phosphate. 

 It is, however, soluble in water and dialyses somewhat 

 slowly through animal membranes. By repeated precipita- 

 tion and again dissolving, aided by dialysis, a solution is 

 obtained which, on evaporating to dryness, gives a whitish 

 yellow powder containing the toxic body, though not in a 

 chemically pure condition. From the characters described 



