488 ANAEROBIC BACTERIA 



sionally a slight odor of butyric acid is noticed; usually there is no 

 sign recognizable either by smell or taste which will furnish a clue to 

 the unfitness of the meat for food. 



Prophylaxis. The disease is not contagious and patients are not a 

 source of danger to others. The organisms are not as a rule found in 

 man. The toxin is thermolabile; consequently thorough cooking of 

 foods will eliminate all danger. Hams, similar meats and meat pro- 

 ducts alone cause the disease. If such meats are cured by pickling 

 they should be immersed in the pickle not less than a week and the 

 pickle should contain the equivalent of 10 per cent, salt solution. 



BACILLUS AEROGENES CAPSULATUS. 



Historical. 1 This organism was first described by Welch in 1891, 

 and later in detail by Welch and Nuttall. 2 It appears to be identical 

 with Bacillus phlegmonis emphysematosse, 3 B. perfringens, 4 B. emphy- 

 sematis vagina?, 5 and possibly B. enteritidis sporogenes 6 and Granulo- 

 bacillus saccharo butyricus immobilis liquefaciens. 7 It is commonly 

 referred to as the "gas bacillus." The organism has been described 

 most commonly in the past as the causative agent of the so-called 

 "foamy organs." It was isolated by Welch from such a case in 1891, 

 and it has been isolated many times since from similar lesions. 



Morphology. B. aerogenes capsulatus is a rather large bacillus, 

 measuring from 1 to 1.2 microns in diameter and from 2 to 5 microns 

 in length, with somewhat square-cut ends, occurring usually singly 

 or in pairs; in artificial culture media rarely in short chains. Accord- 

 ing to Welch, the organism tends to form chains in bloodvessels. The 

 organisms under these conditions may be somewhat shorter than 

 those typically found in artificial media, frequently being but 1.5 

 to 2 microns in length. 



The organism is non-motile and possesses no flagella. It forms 

 capsules in the animal body and occasionally in albuminous media. 

 It also forms spores, first observed by Dunham. 8 The spores are 



1 For an excellent study and critical summary see Simonds, Monograph V, Rockefeller 

 Institute for Medical Research, September 27, 1915. 



2 Johns Hopkins Bull., 1892, iii, 81. 



3 Frankel, Centralbl. f. Bakt., 1893, xiii, 13. 



4 Veillon and Zuber, Arch, de med. exper. et d'anat. path., 1898, x, 517. 



5 Lindenthal, Wien. klin. Wchnschr., 1897, x, 3. 



6 Klein, Centralbl. f. Bakt., 1895, xviii, 737. 



7 Schattenfroh and Grassberger, Centralbl. f. Bakt., ii abt., 1899, v, 209; Miinchen. 

 med. Wchnschr., 1900, Nos. 30-31; Wien. klin. Wchnschr., 1900, No. 48. 



8 Johns Hopkins Bull., 1897, viii, 68. 



