16 SPONTANEOUS GENERATION. 



The materials of the infusion were put into a flask, and a cork 

 a, through which was passed a glass tube, drawn to a neck at >, 

 was pushed deeply into the mouth of it. The space above the 

 cork was filled with an adhesive cement d, composed of resin, 

 wax, and varnish. The glass tube was bent at a right angle, and 



A B C 



inserted into an iron tube c, and cemented there with plaster of 

 Paris c. The iron tube was filled with wires/, leaving only very 

 narrow passage-ways between them. 



" (2) Others (as in Expts. vi., xii., xvi. to xxiii., and xxxi. to 

 xxxiii. inclusive) were prepared as in fig. B, in which the joining 

 at a, fig. A, is avoided, and the iron tube is cemented directly 

 into the mouth of the flask, the neck of which is drawn out at b, 

 to render the sealing of it easy ; otherwise the conditions are the 

 same as in fig. A. 



" (3.) In other experiments (as in Expts. xxiv. to xxviii., and 

 xxxiv. to xxxvii. inclusive) the flask, fig. C, was sealed at the 

 ordinary temperature of the room, and submerged during the 

 period of the experiment in boiling water. This was the method 

 followed by Needham and Spallanzani, and has the merit of 

 eliminating all suspicions of error which might be supposed to 

 arise from some imperfections in the joinings. 



" In the first and second methods, the solution in the flask ia 

 boiled, and at the same time the iron tube filled with wires is 



