THE TALKING PHONOGRAPH. 681 



the end of three days, at the end of three weeks, it is innocent of bacterial 

 life. While both liquids are able to feed the bacteria, and to enable them 

 to increase and multiply after they have been once fully developed, only 

 one of the liquids is able to develop the germinal dust of the air into active 

 bacteria. The mineral solution, to take an illustration from higher life, 

 can feed the chick but can not develop the Qgg. But this is not the infer- 

 ence which has been drawn from experiments with the mineral solution. 

 Seeing its ability to nourish bacteria when once inoculated with the living, 

 active organism, and observing that no bacteria appeared in the solution 

 after long exposure to the air, the inference was drawn that neither bacte- 

 ria nor their germs existed in the air. Throughout the Germany the ablest 

 literature is infected with this error. The death-point of bacteria is 

 another important subject. The experiments already recorded show that 

 there is a marked difference between the dry germinal matters of the air, 

 and the wet, soft and active bacteria of the putrefying organic liquids. The 

 one can be luxuriantly bred in the saline solution, the others refuse to be 

 born there, while both of them are copiously developed in a sterilized tur- 

 nip infusion. If we boil our muddy mineral solution, with its swarming 

 bacteria, for five minutes, not one of them escajDes destruction in the soft, 

 succulent condition in which they exist in solution. The same is true of 

 the turnip infusion, if it be inoculated with the living bacteria only — the 

 serial dust being carefully excluded. But the case is entirely different when 

 we inoculate our turnip infusion with the desiccated germinal matter afloat 

 in the air. Dr. Tyndall proceeded to explain the system of killing germs 

 by boiling a liquid repeatedly for a short time. Those which are not killed 

 begin to sprout, and are destroyed at the next boiling, when they are in 

 their most tender, helpless and unprotected condition. — Nature. 



THE TALKING PHONOGRAPH. 



Mr. Thomas A. Edison recently came into this office, placed a little ma- 

 chine upon our desk, turned a crank, and the machine inquired after our 

 health, and asked how we liked the phonograph, informed us that it was 

 very well, and bid us a cordial good night. These remarks were not only 

 perfectly audible to ourselves, but to a dozen or more persons gathered 

 around, and they were produced by the aid of no other mechanism than the 

 simple little contrivance explained and illustrated below. 



The principle on which the machine operates we recently explained 

 quite fully in announcing the discovery. There is, nrst, a mouth piece, A, 

 across the inner orifice of which is a metal diaphragm, and to the 

 centre of this diaphragm is attached a point, also of metal. B is a brass 

 cylinder supported on a shaft which is screw-threaded and turns in a nut 

 for a bearing, so that when the cylinder is caused to revolve by the crank 

 C, it also has a horizontal travel in front of the mouthpiece, A. It will be 



