EXPERIMENTS MADE IN 1906 35 



of a dilute solution of sodium silicate and dilate 

 phosphoric acid, together with a few grains of 

 ammonic phosphate. 



Portions of these solutions were introduced into 

 sterilised tubes of soft glass about one inch in 

 diameter and three inches long, but drawn out be- 

 yond to a tapering extremity. 1 When about half 

 filled with one or other of the experimental solu- 

 tions, the necks of the tubes were carefully sealed 

 with the aid of a Bunsen's burner, and the tubes 

 were subsequently immersed in a calcium chloride 

 bath, which was raised to temperatures ranging 

 from 115 to 130 C. for from ten to twenty 

 minutes. 



These sealed and heated tubes were then ex- 

 posed, to diffuse daylight, or else were placed in 

 an incubator maintained at a temperature of 30- 

 33 C. In the former case they were kept on a 

 tray just inside a window facing the East, which 

 remained open day and night, because I had pre- 

 viously found that growth and multiplication of 

 Bacteria and Torulas occurred in these saline solu- 

 tions under the influence of diffuse daylight 

 more readily than in similar solutions kept 



1 These were always made for me by Messrs. Miiller, Orme, 

 & Co. of 148 High Holborn, W.C. 



