692 THE POPULAR SCIENCE MONTHLY. 



and, keeping it in a warm place, may await the result, as I have often 

 done. After a variable time, the previously-heated fluid within the 

 hermetically-sealed flask swarms more or less plentifully with bacteria 

 and allied organisms." 



Previously to readitig this statement, the author had operated upon 

 sixteen tubes of hay and turnip infusions, and upon twenty-one tubes 

 of beef, mackerel, eel, oyater, oatmeal, malt, and potato, hermetically 

 sealed while boiling, not by the blow-pipe, but by the far more handy 

 spirit-lamp flame. In no case was any appearance whatever of bac- 

 teria or allied organisms observed. The perusal of the discussion just 

 referred to caused the author to turn again to muscle, liver, and kid- 

 ney, with the view of varying and multiplying the evidence. Fowl, 

 pheasant, snipe, partridge, plover, wild-duck, beef, mutton, heart, 

 tongue, lungs, brains, sweetbread, tripe, the crystalline lens, vitreous 

 humor, herring, haddock, mullet, cod-fish, sole, were all embraced in 

 the experiments. There was neither mistake nor ambiguity about the 

 result. One hundred and thirty-nine of the flasks operated on were 

 exhibited, and not one of this cloud of witnesses offered the least 

 countenance to the assertion that the liquid within flasks boiled and 

 hermetically sealed swarms subsequently more or less plentifully with 

 bacteria and allied organisms. 



The evidence furnished by this mass of experiments that Dr. Bas- 

 tian must have permitted errors either of preparation or observation 

 to invade his work is, it is submitted, very strong. But to err is hu- 

 man ; and, in an inquiry so difficult and fraught with such momentous 

 issues, it is not error, but the persistence in error for dialectic ends by 

 any of us, that is to be deprecated. The author shows by illustrations 

 the risks of error run by himself. On October 21st, he opened the 

 back-door of a case containing six test-tubes filled with an infusion of 

 turnip, whicb had remained perfectly clear for three weeks, while 

 three days sufficed to crowd six similar tubes exposed to mote-laden 

 air with bacteria. With a small pipette, he took specimens from the 

 pellucid tubes, and placed them under the microscope. One of them 

 yielded a field of bacterial life monstrous in its copiousness. For a 

 long time he tried vainly to detect any source of error, and was pre- 

 pared to abandon the unvarying inference from all the other experi- 

 ments, and to accept the result as a clear exception to what had pre- 

 viously appeared to be a general law. The cause of his perplexity 

 was, however, finally traced to the tiniest speck of an infusion con- 

 taining bacteria, which had clung, by capillary attraction, to the point 

 of one of his pipettes. 



Again, three tubes containing infusion of turnip, hay, and mutton, 

 were boiled on November 2d under a bell-jar containing air so care- 

 fully filtered that the most searching examination by a concentrated 

 beam failed to reveal a particle of floating matter. At the present 

 time, every one of these tubes is thick with mycelium, and covered 



