IGO JOURNAL OF THE [December, 



them as in the first series. This new series was commenced in 

 May, 1 886. In jar A roiled water was put, the demijohn having 

 been purposely shaken. Jar B was supplied with water which 

 1 decanted carefully before shaking the demijohn. The water 

 was a second time roiled and enough of it filtered to fill jar C, 

 the filter paper at the start passing loo drops per minute, but 

 requiring 90 minutes to filter a pint. This jar C was then placed 

 beside jar B. The filter used was laid aside and kept wet. I 

 then shook the demijohn again, and took from it enough roiled 

 water to fill two jars. This was carefully filtered, and the 

 filters were kept. This filtered water was then boiled for twenty 

 minutes and, when quite cool, enough to fill it was poured into 

 jar Z>, which was then placed in the window by the side of C. 

 In jar E the remainder of the cooled water was put, and in it 

 were washed all the filter papers that had been used. Jar E 

 was then set next to D. It should be noted that the jars of this 

 series were subjected to a lower temperature than were those of 

 the first series — a circumstance entirely unavoidable. For two 

 weeks the tops of the jars were uncovered, thus exposing the 

 water in them to the air, which, as microscopists know, is mis- 

 chievously prolific of germs of confervas and infusoriee. How- 

 ever, this could not vitiate my work. Called away from home 

 almost constantly by my official duties, I gave the jars no serious 

 inspection until in the first part of the month of July. I then 

 found in ^ a fine crop of diatoms, though they were not so 

 numerous as they were in jar A of 1882. I observed with 

 some surprise that the Naviculx were now greatly in the as- 

 cendant. In fact, of the genera Nitzschia and Aviphora there 

 were very few representatives. I next examined B. To this 

 jar I had looked for results equivalent to those of D in the first 

 series, but could scarcely believe my eyes when, after many dips 

 had been examined, I could find only one diatom, a Navicula. 

 The film at the bottom of the jar was made up of one-celled 

 confervse. The water had been decanted so carefully that the 

 spores, which doubtlessly lay on the sediment in the bottom of 

 the demijohn, had not passed out with the water. Hence I 

 infer that the spores are resting and not motile spores. 



Jar C was next examined. Into this the roiled water had 

 been filtered. It contained a rich crop of diatoms consisting 

 almost wholly of Naviculce, the Nitzschia and Amphorcc being 



