548 PATHOGENIC ANAEROBIC BACILLI. 



dried in vacuo at 20 to 22 C. The purified toxin as thus obtained had a 

 slightly yellowish color, and was in the form of transparent scales, which 

 were odorless, tasted like gum acacia, and were easily soluble in water. The 

 chemical reactions of this purified toxin, according to Brieger and Cohn, show 

 that it is not a true albuminous body. When injected beneath the skin of a 

 mouse weighing fifteen grammes, in the dose of 0.00000005 gramme, it causes 

 its death, and one-fifth of this amount gave rise to tetanic symptoms from 

 which the animal recovered after a time. The lethal dose for a man weigh- 

 ing seventy kilogrammes is estimated by the authors named to be 0.00023 

 gramme (6.23 milligramme). Comparing this with the most deadly vege- 

 table alkaloids known it is nearly six hundred times as potent as atropin and 

 one hundred and fifty times as potent as strychnin. 



Fermi and Pernossi (1894), as a result of an elaborate research, have deter- 

 mined many of the chemical characters of the tetanus toxin. "When in solu- 

 tion it is destroyed by a comparatively low temperature (55 C. for one hour) 

 and by exposure to direct sunlight, but the dry powder resists a temperature 

 of 120 C. It has not the properties of an alkaloid, as it is not dissolved by 

 any of the usual solvents of these bodies the only solvent thus far discovered 

 is said to be water. It resembles the albumins and peptones in its failure to 

 pass through a dialyzing membrane. The authors last referred to conclude 

 their summary of results as follows : 



"The appended table shows that the tetanus poison, like that of diphtheria, 

 in its behavior as regards the action of light, heat, chemical agents, and 

 dialysis, as also its solvents, the agents which precipitate it, and its action upon 

 living animals, closely resembles the poisons of serpents (Naja tripudians, 

 Crotalus, etc.). As to the chemical nature of this group of substances, we can 

 at present only say that they rather have the characters of colloidal sub- 

 stances than otherwise, and more nearly resemble the albuminoid bodies than 

 the bases. We do not, however, reject the very probable hypothesis that 

 these toxins are acids or bases, or other very unstable, peculiar substances 

 which are closely united with colloidal substances, as is the case, for example, 

 with the alkali and acid albumins and so many other albuminous bodies." 



While the exact nature of the toxic substance contained in tetanus cul- 

 tures has not been determined, we probably cannot, at present, do better than 

 to continue to speak of it as a '* toxalbumin." 



Symbiosis. Car bone and Perrero (1895), in a case of so-called rheumatic 

 tetanus, in which there was no evidence of a wound through which infection 

 might have occurred, obtained the tetanus bacillus, by inoculations in mice, 

 from an exudate into the larger bronchial tubes. The micrococcus of pneu- 

 monia was also present, and the authors named report that as a result of asso- 

 ciation with this coccus the tetanus bacillus is able to grow in the presence of 

 oxygen. Other bacteriologists had previously reported that the tetanus bacil- 

 lus is able to grow in mixed cultures in the presence of oxygen, and this has 

 been confirmed by the recent researches of Kedrowski (1895). Righi ( 1 6 

 claims that the tetanus bacillus may acquire the faculty of growing in the 

 presence of oxygen, when it is gradually habituated to the presence of this 

 gas. Penzo has observed a similar modification in the biological characters 

 of the bacillus of malignant oedema ; and Kitt (1895) has succeeded in obtain- 

 ing aerobic cultures or the bacillus of symptomatic anthrax. He says : ' ' The 

 bouillon cultures do not always develop anaerobic ; one must inoculate sev- 

 eral half-litre flasks and place them in the incubating oven ; some remain 

 clear and without evidence of development, however long they are kept ; 

 others begin to ferment at the end of two days. Sometimes this formation of 

 gas only lasts for a day ; again, with more vigorous development, it may last 

 for several days, and the contents of the flasks have the appearance of bubbl i ii^ r 

 champagne or 1 1 V /.s.s- bier. When a culture is once obtained in this way there 

 is no difficulty in making a series of aerobic cultures. 



