Thermal Death-point of Monad Germs. By TV. H. Ballinger. 1 1 



the spore-emission from the sac by steadily following a given form 

 through some of the familiar preceding stages into the condition of 

 the still sac from which the spore is emitted, and seeing the emission 

 take place. This must be effected in the moist chamber stage 

 devised, as will be remembered, for constant observation, without 

 the evaporation of the fluid containing the organisms. But under 

 ordinary circumstances it would be impossible, when the contents 

 of a sac had been seen to be emitted, to transfer them from this 

 stage to the piece of apparatus for heat testing. To do this, however, 

 a piece of very thin cover-glass was made to rest upon the floor of 

 the stage, and take its place, having the drop of fluid to be examined 

 placed upon it, and covered as usual. But both of these delicate 

 pieces of glass had been marked in convenient places with the 

 diamond, to facihtate subsequent fracture into small pieces. In this 

 way, then, with the stage worked in the usual way, the fluid was 

 hunted and watched, and fresh drops taken if needful, until a cyst of 

 the form under examination was found, and then watched, until it 

 opened and deposited its spores. The circles of thin glass on 

 which this happened were immediately taken ofl" the stage, and 

 broken in the funnel B, Fig. 4, the cell of which had been pre- 

 viously properly prepared. A quantity of the septic fluid con- 

 taining the organism was now poured down the tube over the glass, 

 washing the whole as it passed and carrying a large number of the 

 delicate broken fragments with it. In this way the larger quantity 

 of the freshly emitted spore was carried into the reservoir A. I 

 select as illustrative of the method of study the same organism as, 

 illustrated our method in finding the death-point of the adult. It 

 is shown at Fig. 11. 



The whole apparatus containing the ffuid (Figs. 2 and 4) was 

 suspended in an oblong copper vessel, and covered with small frag- 

 ments of solid white paraffin, the temperature of which was, after 

 melting, indicated by thermometers, and this allowed of a slow 

 raising of the fluid to the boiling-point, as indicated by gentle 

 ebullition in the bulb A. This was continued for five minutes. The 

 tube J, Fig. 4, was then hermetically closed before the ebullition had 

 ceased, and the whole was removed from the paraffin, and the cell 

 carefully wiped whilst hot. The piece of platinum H was now 

 shaken sharply upon the septum F, and the calcined air contained 

 in E was admitted into the bulb A, the platinum remaining on the 

 top of the passage G, which is too small to admit of its entrance 

 iuto A. 



In this way it will be seen that the normal conditions of the 

 fluid were as far as possible restored. 



I at once proceeded to microscopical examination, employing an 

 immersion lens giving 1200 diameters. Nothing could at first be 

 seen but powerful Brownian movement of the smaller particles 



