EDWIN O. JORDAN 447 



paratyphoid group throw Hght on the ordinary sources of food poisoning with these 

 organisms. First and foremost is the use of meat or other food substance derived 

 from aihng animals, an origin already rendered plausible by epidemiological observa- 

 tions. Since many kinds of food animals are liable to paratyphoid infection and since 

 human paratyphoid infections (or intoxications) are usually sudden, of brief duration, 

 and with low fatality and hence relatively rarely subjected to competent investiga- 

 tion, outbreaks of this type are probably more common than represented by definite 

 records. Another possibility of paratyphoid infection is from the use of food con- 

 taminated by animal-carriers of paratyphoid bacilli. Rats and mice are probably the 

 greatest offenders in this respect, and the protection of cooked food from these vermin 

 is a desideratum. The use of bacterial rat viruses containing living paratyphoid 

 bacilli is highly objectionable. 



The relative share of Hving paratyphoid bacilli and of their toxic products in the 

 production of food poisoning outbreaks is quite obscure. There are numerous in- 

 stances^ in which pronounced symptoms have followed within two hours after the 

 ingestion of the incriminated food, and in which formed poisonous substances rather 

 than an infective process are accordingly deemed responsible. Many outbreaks ap- 

 pear to give indications of both toxic action and infection. The toxicity of cultures 

 of various paratyphoid bacilli has been studied by a number of observers.^ Ecker,^ 

 who worked with broth cultures, was led to believe in the existence of soluble toxic 

 substances, although most previous investigators had considered that the paratyphoid 

 toxins were "endotoxins." Miss Branham, however, regards the paratyphoid toxins 

 as contained within the cell during life and as set free only on cell disintegration. In 

 animal experimentation, culture filtrates have been found toxic for rabbits and mice, 

 though not for guinea pigs, when injected intravenously, but show no effect when 

 given by other routes. Symptoms of intoxication follow the introduction of the toxic 

 filtrate into the blood stream after about forty to forty-five minutes, irrespective of 

 whether the dose is lethal or sublethal. The toxic cultures and filtrates are definitely 

 thermostabile and withstand boiling for a considerable period without loss of toxic 

 power. Cultivation in protein-free medium yields a toxic filtrate which gives rise to 

 definite antibody formation: agglutinins, precipitins, complement-fixing antibodies, 

 and possibly antitoxins. ^ 



2. CL. BOTULINUM, VARIETIES A, B, AND C 



The spindle-shaped, anaerobic, spore-bearing rods classed in the genus Clostridi- 

 um and distinguished by their unique ability to generate a true toxin that is poisonous 

 when swallowed, constitute a specific group of micro-organisms. The three known 

 varieties differ in various respects, among others with regard to toxicity. Type A 

 producing by far the most potent toxin, the ratio of lethal dose for the three Types 

 A, B, and C being given by one author as i : 50: 125.S 



'Cf. Savage, W.,G.: Rep. Loc. Gov. Bd. (N.S.), No. 77. 1913; Savage, W. G., and White, B.: 

 op. cit.. No. g2. 1925. 



^ Cf. summary of Branham, S. E.: /. Inject. Dis., 37, 291. 1925. 



3 Ecker, E. E.: ibid., 21, 541. 1917. 



4 Branham, S. E., and Humphreys, E. M.: ibid., 40, 516. 1927. 



5 Bengtson, I.: Studies on Organisms Concerned as Causative Factors in Botulism, Bull. 136, Hyg. 

 Lab. Pp. loi. 1924. A full discussion of the early Hterature on botulism has been given by Dickson 



