Hudson. — On Spontaneous Generation. 185 



Torula, Bacillus, and Micrococci. Ifc will be well now to examine briefly 

 some typical experiments of the leading heterogenists — Pouchet, Jeffreys 

 Wyman, and Bastian. 



Poncbet in one of bis experiments introduces a flask into a vessel con- 

 taining a decoction of barley wbich had been kept boiling for six hours ; the 

 flask being completely filled with this fluid was brought to the surface and 

 corked, and then the circumference of the cork was surrounded by varnish. 

 On the sixth day a deposit of yeast was seen, and the flask burst on the 

 seventh. 



Here an impure vessel, cork etc., were used, and the heat was not 

 applied to them for a sufficient length of time. Further, the fluid cannot 

 have been boiling when the vessel was introduced and corked, otherwise, if 

 he bad done it efficiently, the operator would have scalded his fingers. It 

 is, moreover, noteworthy that Poucbet only got organisms in one experi- 

 ment of this kind. 



I may here say that Pasteur has completely upset all of Pouchet's 

 experiments and deductions. 



In Jeffreys Wyman's experiments such fluids as sugar gelatine and hay 

 infusion, or flesh sugar and gelatine, were put into a flask, the neck of 

 which was drawn out and bent at right 

 angles, the extremity of the neck was in- 

 serted into an iron tube and cemented 

 there with plaster of Paris. The iron 

 tube was filled with wires, leaving only 

 very narrow passage-ways between them. 

 The general relation between the quantity 

 of fluid and the capacity of the flask was 

 about 20 to 500. The flasks were then boiled for periods varying between 

 a quarter and two hours, while at the same time the iron tube containing 

 the wires was heated to redness. On withdrawing the lamp from the flask, 

 tbe air which entered passed over these heated iron wires. When cold the 

 flasks were sealed with the blowpipe. Fourteen vessels were prepared in 

 this way, and in ten of these, when opened after the lapse of various periods 

 of time, Vibriones and Bacteria were found. The other four remained barren. 



Curiously enough, Pasteur had made numerous experiments almost 

 exactly similar and had obtained no organisms. "Why this different result ? 

 Pasteur's flasks were half filled with fluid, while Wyman's contained only 

 from 2W0 part, so that we can easily understand that in Wyman's 

 experiments a portion of the air and of the walls of the flask were never 

 heated to within many degrees of the boiling point. Another source of 

 fallacy is to be found in the fact that the air which passes through the iron 

 tube with its contained wires is only exposed to dry heat, and it is within 



