80 Dr. J. \Vi/ man— Experiments on Infusoria. 



xxix and xxx inclusive) they were prepared as in fig. 1. The ma- 

 terials 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 inserted into an 

 iron tube e, and cemented there with plaster of paris c. The 

 iron tube was filled with wires/, leaving only very narrow pas- 

 sage ways between them. = 



(2.) Others (as in Exps. vi, xii, xvi to xxiv, and xxxi to xxxiii 

 inclusive,) were prepared as in fig. 2, in which the joining at a, 

 fig. 1, 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. 1. 



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

 xxxiv to xxxviii inclusive,) the flask, fig. S, 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 elim- 

 inating 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 is 

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

 heated to redness. While the contents are boiling the steam 

 formed expells the air from the flask ; when the boiling has con- 

 tinued long enough, the heat is withdrawn from beneath the flask, 

 and as the steam condenses, the air again enters through the iron 

 tube, the red heat of which is kept up, so that all organ is 

 contained in the air are burned. 



may be uaed many times. 





. methods the : 



