516 Messrs. W. E. Bullock and W. Cramer. On a New 



B. cedematiens experiments were made only with spores, for the reasons 

 already given, and for these larger doses are necessary to elicit their patho- 

 genic action, namely, 5 mgrm. for a mouse and 10 mgrm. for a guinea-pig. 

 In all our experiments the solutions of calcium salts were used in a strength 

 of 1 per cent, or 2 per cent. It is possible that the dose of calcium salt 

 necessary to produce the effect may vary with the concentration. This point 

 has not yet been tested by us. 



For the sake of convenience and brevity it is advisable to designate this 

 new phenomenon by a new name. For reasons which will be given below, 

 and which are based on the mechanism by which the phenomenon is produced, 

 the terms " kataphylaxis," or " defence-rupture," will be used in this paper to 

 describe it. The smallest dose of a calcium salt necessary to elicit the specific 

 disease from the detoxicated bacteria in every case is called the " minimal 

 rupturing dose." Smaller doses which are still capable of eliciting the specific 

 disease, but are not capable of doing so in every case, are called " subminimal 

 rupturing doses." In fixing these doses it is of course assumed that a 

 virulent strain of the specific bacteria is being used. The density of the 

 bacterial suspensions can apparently be varied within wide limits without 

 affecting the results. We have worked, as a rule, with a suspension of such 

 a density that large print is just readable through it in a test-tube. But we 

 have also used denser and more dilute suspensions with practically identical 

 results. 



Calcium nitrate and calcium acetate have the same effect as calcium 

 chloride. The insoluble calcium carbonate has no rupturing action. 

 Similar doses of the chlorides of potassium, sodium, ammonium, magnesium, 

 and strontium* have no effect when injected together with a suspension of 

 B. Welchii. 



B. sporogenes, when injected together with calcium chloride, does not 

 produce gas gangrene, and does not even make the animal ill. It may be 

 recalled that even in broth cultures this organism is non-pathogenic, if 

 present alone. 



The rupturing action of calcium chloride is abolished by sodium citrate. 

 As an illustration the following experiment will be given. A number of 

 mixtures of 2 per cent, solutions of calcium chloride and sodium citrate were 

 made up to a volume of 2 c.c. with water. Two drops of a dense freshly 

 prepared suspension of B. Welchii in saline were added to these mixtures ; 



* [JVote added April 4. — "We have since found that with Vihrion septique, the patho- 

 genic properties of which are more readily elicited than those of B. Welchii, strontium 

 will produce gas gangrene, if sufificiently large doses (5 mgrm. -10 mgrm.) are given. But, 

 even then, a positive result is not obtained in every animal, as is the case with B. Welchii.'] 



