BACILLUS WELCH 1 1 525 
(b) Cultural.— Make anaerobic glucose gelatin plates and blood- 
agar plates from the suspected material, selecting portions which are 
remote from contaminated surfaces, as follows: (1) Rapidly make a 
maceration of some of the susi)ected material in sterile salt solution. 
(2) Heat some of the opalescent fluid thus obtained to ()()° (\ for thirty 
minutes, and make plates. (8) Add some of the opalescent fluid to 
fermentation tubes according to Theobald Smith's method (see page 
51 1) with bits of sterile animal tissue. (4) Plate some of the opalescent 
fluid directly without heating into glucose gelatin plates. (5) Examine 
the media for characteristic colonies. 
(c) Identification of To.vin. — l. Filter some of the macerated material 
rapidly through sterile filter paper and inject 0.5 to 1 cc. subcutan- 
eously into a rabbit or a guinea-])ig and into a chicken. The protruding 
eyeballs and respiratory failure usually suffice to establish the diag- 
nosis in the mammal. The production of limber neck in the chicken is 
equally suggestive. The diagnosis may be confirmed by staining sec- 
tions of the central nervous system and identifying the lesions. (2) 
Add 2 to 5 cc. of the filtrate to some bread and feed a rabbit and a 
chicken with it. Note the symptoms. (3) P'ilter some of the broth 
from the fermentation tube in Step 3 of the cultural identification and 
inject subcutaneously or feed to a rabbit and observe the symptoms. 
(d) Inspection of Suspected Food. — It is difficult usually to detect 
anything abnormal in food in w^hich B. botulinus has grown. Occa- 
sionally a slight odor of but>ric acid is noticed; there may be no sign 
recognizable either by smell or taste, however, which will furnish a 
clue to the unfitness of the food for human consumption. 
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 immediately before eating will eliminate all danger. Hams, 
similar meats and meat products, canned vegetables, oli\-es and other 
vegetables or fruits which are imperfectly preserved may cause the 
disease. 
Bacillus botulinus is rather widely distributed, and it is apparently 
quite commonly foimd in the Pacific Coast states. Its habitat, how- 
ev-er, is unknown. Its inability' to grow" well at the temperature of 
the mammalian body would appear to exclude animal hosts. On 
the other hand, the frequence with which imperfectly preserved vege- 
tables have been associated with botulism would suggest the soil as 
a possible habitat. 
BACILLUS WELCHn. 
Historical.;- B. welchii was isolated and described by Welch in 1S91, 
and later in detail by Welch and Nuttall,'' under the name B. aerogenes 
1 Easton and Meyer: Jour. Infec. Dis., 1924, 35, 207. 
- For an excellent study and summary see Simonds (Monograph No. v, Rockefeller 
Inst, for Med. Res., September 27, 1915. 
3 Bull. Johns Hopkins Hosp., 1892, 3, 81. 
