344 



Rev. W. H. Dallinger on 



[May 2, 



and this tube terminates in a delicate closed and flattened cell 0. In 

 a microscopical point of view this cell is the most important part of 

 the apparatus. It is a flattened bulb, and its upper and under walls 

 are films of glass, varying in different pieces of the apparatus from 

 the -^th to the -g-^th of an inch in thickness ; and the space between 

 these walls may vary from the -^-th to the T ^o^ n °^ a]DL inch in depth. 



We thus have a perfect cell, completely closed, the contents of 

 which can readily be studied with the aid of the most powerful lenses. 

 The walls of the cell are of course not as absolutely even and smooth 

 as the thin " covering glass " usually employed with high power 

 lenses : but it is in the majority of cases beautifully level and clear, 

 when the manner of its production is remembered. Of course I 

 should never have employed these cells for the purpose of discovering 

 delicate and unknown details ; but they answer admirably for deter- 

 mining the presence or absence of phenomena, the nature of which is 

 well known beforehand. 



It is manifest then, that if a fluid be put in the bulb and stand at 

 the level of the dotted line A, that it will fill and be in communication 

 with the cell C. 



E is a hollow bulb filled with calcined air, and hermetically sealed ; 

 but it does not communicate with the bulb A on account of the presence 

 of a thin glass partition or septum F. The object of this is, that when 

 by boiling, the air has been driven out of the bulb A, and the whole 

 interior space has been hermetically sealed at J, air may be again in- 

 troduced ; which is accomplished thus : H is a pointed piece of pla- 

 tinum wire, heavy enough by a sharp shake to break the septum F, 

 but too large in diameter to pass through the neck G, but of course 

 the calcined air immediately enters and restores to the fluid its normal 

 conditions. 



Fig. 27 is precisely the same as the above, the same letters referring 

 to the same parts in both ; but it has an addition to it marked MN. 

 This is a tube opening at N into the bulb A, but until needed the 

 communication of the tube with the interior of the bulb is prevented 

 by the thin partition L. The object of this is, that supposing a given 

 infusion to have become sterilized in relation to a certain organism, 

 by any ascertained temperature, to determine whether nevertheless 

 the fluid is still capable of sustaining the organism if it be reintro- 

 duced. To do this, a piece of platinum wire, as before, is taken and 

 touched with a fluid in which the living organism abounds ; it is then 

 placed in the tube K. The tube is then sealed at M ; the piece of 

 platinum is shaken sharply, breaks the septum L, and falls into the 

 fluid, inoculating it. In relation to the particular organism now 

 being considered, this, however, was not required. 



The first important matter to be taken into account was the death 

 point of the adult. A piece of apparatus similar to fig. 26 was used. 



