1871.] Mr. F. Grace- Calvert cn Protoplasmic Life. 



4C9 



preparation of pure distilled water. Having always found life in distilled 

 water prepared by the ordinary methods, by keeping it a few days, after 

 many trials I employed the following apparatus, which gave very satisfac- 

 tory results, as it enabled me to obtain water which remained free from life 

 for several months. 



It consists of two flasks, A and B (A rather larger than B), fitted with 

 perforated caoutchouc stoppers*. These flasks are connected by the tube 

 D. Into the stopper of A is fitted a tube C, to which is joined a piece of 



caoutchouc tubing, which may be closed by the clip E. Through the 

 stopper of B is a siphon, F, the long limb of which is cut and joined with 

 caoutchouc tubing, which can be closed by the clip G. Through this 

 stopper is a third tube, IT, connected by caoutchouc with the tube I ; this 

 can be closed by the clip K. The tube I is about 3 feet long, and goes 

 into the vessel L, which is partly filled with water. 



The water to be distilled is mixed with solution of potash and perman- 

 ganate of potash, and placed in the flask Af . Before distillation is com- 

 menced, a rapid current of pure hydrogen, or some other gas, must be 

 passed through the apparatus by the tube C to displace the air and carry 

 off all the germs the air may have contained. The clip G is first left open, 

 then this closed and the clip K opened, which allows the gas to pass 

 through the water in the vessel L. 



* The stoppers and caoutchouc tubing used for the various joints must be new, and 

 must be well boiled in water before use. 



f The reasons why I employed permanganate of potash (in large excess) were that, 

 under the influence of heat, its oxidizing powers were much increased, and that it gave 

 off no gas that could interfere with the purity of the water, this salt in solution not even 

 yielding oxygen under any circumstances. 



