1876] 
be utilized with the best results in determining the existence of 
bacteria-germs. To bring the idea to a practical result a num- 
ber of chambers were constructed with glass fronts. At two 
opposite sides facing each other a couple of panes of glass were 
placed to serve as windows, through which the electric beam 
might pass. A small door was placed behind, and an ingenious 
device was arranged to enable a germ-tight pipette to have free 
lateral, as well as vertical, motion. Connection with the outer 
air was preserved by means of two narrow tubes inserted air- 
tight into the top of the chamber. The tubes were bent several 
times up and down, “ so as to intercept and retain the particles 
carried by such feeble currents as changes of temperature might 
cause to set in between the outer and the inner air.” 
Into the bottom of the boxes were fitted air-tight large test- 
tubes, intended to contain the liquid to be exposed to the action 
of the moteless air. 
“On September 10th the first case of this kind was closed. 
The passage of a concentrated beam across it showed the air 
within it to be laden with floating matter. On the 13th it was 
again examined. Before the beam entered, and after it quitted 
the case, its track was vivid in the air, but within the case it 
Vanished. Three days quite sufficed to cause all the floating 
matter to be deposited on the sides and bottom, where it was 
retained by a coating of glycerine, with which the interior sur- 
of the case had been purposely varnished. ‘The test-tubes 
Were then filled through the pipette, boiled for five minutes in 
: Tos of brine or oil, and abandoned to the action of the mote- 
ess air,” 
Spontaneous Generation. 417 
on this way the air in its normal condition was freely supplied 
=a e Infusions, but of mechanically suspended matter it could 
: demonstrated that there was none. And it was proved, with’ 
' clearness that admits of no quibble, that infusions of every 
| » animal or vegetable, were absolutely free from putrefactiye 
reahisms, «Ty no single instance . . . . did the air which ha 
Proved moteless by the searching beam show itself to pos- 
o ag least Power of producing bacterial life or the associated 
- “nomena of putrefaction.” But portions of the same infusions 
: ay to the common air of the Royal Institution Laboratory 
: ria ntinuous temperature of from 60° to 70° Fahr. fell inva- 
en ey putrefaction ; and when the tubes containing them 
9 d to 600 in number not one of them escaped infection — 
= de all “infallibly smitten.” Here is irresistible evidence 
TRO 7, 27 : 
