Bache.] [April 17, 



makes no pretense to destroy the micro-organisms, but merely 

 to neutralize as much as possible their injurious action in the 

 human economy, simpty by entrapping them. What I contend, 

 however, is that the best process of sterilization is that which 

 does not seek to entrap micro-organisms, with the inseparable 

 danger of their partial or almost entire escape alive, but that 

 which, with abstention from their purposive arrest, kills, and 

 allows them as free passage as possible to the stomachs of city 

 dwellers. It will probably be thought at this point, with a very 

 usual misconception, as that which we have in the Anderson 

 process has proved quite efficacious, whereas that of which I 

 speak is but an ideal, perhaps impossible of attainment, that I 

 am proposing to accept a shadow for the substance of a thing. I 

 would grant the cogency of the thought, had I ever intended to 

 make denial of the excellence of the Anderson process, and pro- 

 posed to offer a possibility in exchange for a reality. But, 

 having taken neither of these positions, I do but state the case in 

 the abstract, and the truth of it in that form being admitted 

 (and I do not see how it can be denied), I have but to add before 

 proceeding that, excellent as is the Anderson process, within its 

 acknowledged lines, it would still be well to consider if the ideal 

 one is not capable of accomplishment by the means which I am 

 about to suggest. 



About two years ago it occurred to me that before experiment- 

 ing with bacteria, with reference to killing bacilli established in 

 the human body, and with reference to the sterilization of city 

 drinking water by electricity, I would pass a current through 

 some water containing protozoa, and observe how much is re- 

 quired to kill them. With this purpose in view I took a glass 

 tube of four inches in length and five thirty-seconds of an inch 

 in calibre, and partially filled it with water teeming with protozoa 

 from hay-infusion, which had previously been examined by me 

 under the high power of a one-tenth microscopical objective, 

 commanding a large field with an' immersion lens, and depending 

 upon which of two eyepieces was used, magnifying from five 

 hundred and fifty to six hundred and fifty diameters. When 

 both ends of the tube had been plugged up with brass eye-screws 

 wrapped with paper, leaving their ends exposed in the tube, the 

 volume of infusion intervening between the ends of the poles 

 thus formed was only two-thirds of a cubic centimeter, and the 



