LIFE HISTORY OF BACILLUS ANTHRACIS. 169 



We now have to mention the results following upon 

 boiling and compression of the spores. 



Since Pasteur stated that the spores of Bacillus remained 

 active after boiling, much has been said about their wonder- 

 ful tenacity of life. Having a fair quantity of spores at our 

 command Dr. Burdon Sanderson suggested that we should 

 test the accuracy of the above statement. Accordingly, 

 along with Dr. Sanderson, I added to the aqueous humour 

 containing the spores a small quantity of distilled water, 

 and after carefully stirring the mixture a mouse was inocu- 

 lated with a few drops, an absolutely clean syringe being 

 used. The rest was boiled for five minutes, and then with a 

 fresh syringe another mouse was inoculated, and so on, after 

 boiling at different periods up to a quarter of an hour. 



The result was that in two days the mouse inoculated 

 with the unboiled spores was found dead, but the others 

 remained absolutely unaffected. Again, spores and rods 

 were treated in exactly the same way and with exactly the 

 same results; the spores were rendered inactive after even 

 two minutes' boiling. But thinking newly cultivated 

 spores might be more easily destroyed than old dried ones, 

 we boiled blood containing spores which had been kept dry 

 for five years. The same results followed ; the mice inocu- 

 lated with the solution before boiling died, those inoculated 

 after boiling were unaffected. 



It may be mentioned that mice are very susceptible ; in 

 no case has the smallest number of spores introduced into 

 the subcutaneous tissue failed to prove fatal. 



We next directed our attention to the other fact men- 

 tioned by Pasteur, viz. that the spores were not rendered 

 inactive when subjected to a pressure of twelve atmospheres 

 of oxygen. M. Bert repeated M. Pasteur's experiment, but 

 found that the spores were destroyed ; hence it was all 

 the more necessary, though, perhaps, a point of little prac- 

 tical importance, to endeavour to make out what influence 

 compression really had. This experiment we were enabled 

 easily to perform through the kindness of Mr. J. Millar 

 Thomson, of King's College, who supplied us with the 

 necessary apparatus. 



The spores were suspended in a solution of distilled water 

 in an ordinary test-tube, which was placed in the cylinder, 

 and twelve atmospheres of oxygen allowed freely to come in 

 contact with them. After subjecting them to this pressure 

 for twenty minutes they were introduced under the skin of 

 a mouse, but without producing any indication of splenic 

 fever or any other abnormal condition. 



