conclude that they 

 naa oeen " spontaneously generated." 



This reasoijing applies word for word to the development of 

 Bacteria from that floating matter which the electric beam reveals 

 in the air, and in the absence of which no ]>acterial life has been 

 generated. There seems- no flaw in this reasoning ; and it is so 

 simi)le as to render it unlikely that the notion of Bacterial life 

 developed from dead di 



members of a great scientific profession. 



A novel mode of experiment has been here pursued, and 

 be urged that the conditions laid down by other investig 

 this field, w •" ■ ■ - 





, vhich have led to different results, have not been strictly 

 attended to. To secure accuracy in relation to these alleged 

 results, the latest words of a writer on this question, who has 

 influenced medical thought both in this country and in America, 

 are quoted. " We know," he says, "that boiled turnip or hay- 

 infusions exposed to ordinary air, exposed to filtered air, to cal- 

 cined air, or shut off altogether from contact with air, are more 

 or less prone to swarm with Bacteria and vibriones in the course 

 of from two to six days." Who the " we" are who possess this 

 knowledge is not stated. The author is certainly not among the 

 number, though he has sought anxiously for knowledge of the 

 Kind. He thus tests the statements in succession. 



And first, with regard to the filtered air. A group of twelve 

 large test-tubes were caused to pass air-tight tlirough a slab of 

 wood. The wood was coated with cement, in which, while hot, 

 a heated " propagating glass" resembling a large bell jar was im- 

 bedded. The air within the jar was pumped out several times, air 

 filtered through a plug of cotton-wool being permitted to supply 

 Its place. The test-tubes contained infusions of hay, turnip, beef, 

 and mutton -three of each— twelve in all. Thev are as i-har and 

 cloudless at the present moment as thev wetv \\\m\\ the day of 

 their introduction; while twelve similar' tul>L's. prtp.ircd ;it the 

 same time in precisely the same way and exposod to the ordinary 

 air are clogged with mycelium, mould, and Burttrln. 



With regard to the 'calcined air, a similar propagating glass 



sions^ The "glass" was exhausted and carefully tilled with air 

 Which had passed through a red-hot platinum tube, eontiuning a 

 roll of red-hot platinum gauze. Tested by the searching beam, 

 tn<- calcuied air was found quite free from floating matter. Not 



while twelve similar tubes placed outside have fallen into rotten- 



