1911.] Disintegrating Bacterial and other Organic Cells. 59 



2. Approximately, every micro-organism or cell should, sooner or later, be 

 brought with certainty under the influence of the grinding action, so that the 

 number of whole cells remaining is a minimum. 



3. The containing vessel in which the grinding action takes place must be 

 so effectually enclosed that during the process of disintegration no cells 

 have any opportunity of escaping. This applies particularly to pathogenic 

 organisms. 



4 The appliance must be such that an efficient cooling arrangement may 

 be adopted, and, if necessary, a temperature of 15° to 20° C. below freezing 

 maintained at the actual point at which the grinding action takes place. 



5. The action presumably requiring to go on in metallic containing 

 vessels, it should be provided that the actual mechanical disintegration of 

 metal between the grinding surfaces should be as little as possible. 



These conditions are in the main complied with in the apparatus to be 

 described (figs. 1 and 2). 



The containing vessel consists of a phosphor-bronze body A, in which 

 a number — usually five — of hardened steel balls, B, are placed. The shape 

 of the containing vessel is such that when these balls are at its periphery 

 they accurately fit the inner side of the vessel. The diameter of the vessel 

 may conveniently be slightly less than the sum of the diameters of three 

 balls. The balls are evenly distributed round the pot by means of a cage C, 

 and, during the time they are running, this cage ensures that they are 

 equidistant and do not collide one with another. At the centre of the 

 metal pot is a steel cone D, which is of such a size that it keeps the balls in 

 their proper position, in close contact with the periphery of the containing 

 vessel. The vessel is closed by a screw cap E, through which the steel cone 

 passes, and in which it is free to rotate. Over the whole of this a metal 

 cylinder F is placed, and is screwed down, completely sealing the upper 

 opening in the metal pot. In the top of this metal cylinder a steel bearing 

 G is placed, which has freedom of movement in a vertical direction, but is 

 kept down on the top of the steel cone by the action of a spring. It 

 therefore follows that when this metal cylinder is screwed down, the steel 

 cone is pressed down on to the balls, and the balls are in their turn forced 

 out to the periphery of the metal pot. The whole appliance is mounted on a 

 cone H, which is the upper end of a shaft passing through the base plate ; on 

 the lower end of the shaft is a grooved wheel K, by which the apparatus may 

 be rotated. 



The grinding action is intended to take place between the steel balls 

 contained in the metal pot and the interior surface of the pot, but it is 

 evident that, so long as the whole appliance is rotated as it stands, no 



