BY ARTIFICIAL MEANS. 



361 



As many other Diatoms develop by preference in the bottom 

 of the vessels, this peculiarity requires special arrangements for 

 observing them. To meet this, I have constructed a new cell 

 (see Fig. Ss). 



.Fig. 8^. — j1, Culture Cell with capillary plate, transverse, full size. 

 L, Glass Slip ; c c, Ring ; m, Cover-glass ; ;/, Thin glass interior ; £, Culture. 

 B, Cell seen on the microscope, full size. L L, Glass Slip ; c c, Ring ; 

 n n, Interior thin glass, supported on three spherules of mastic. 



On a glass slip, which is bored towards its upper edge with a 

 hole about 2 mm. in diameter, there is cemented, by means of 

 mastic, an unbroken ring, and on the ring a cover-glass. In this 

 way you have a new cell, of which the aperture is lateral, which 

 can be held vertical during observation, but can be laid in a hori- 

 zontal position during the culture, with the cover-glass downwards. 



Thus the deposits, instead of forming in the lowest parts of 

 the ring, remain and encrust the cover-glass, and the Diatoms that 

 are sown in the little cells are born and multiply on the inner 

 face of the cover-glass, which admits of following their growth for 

 many months, with objectives of all sorts. 



This arrangement also admits of your treating the algae with 

 different re-agents that can be introduced by the lateral opening 

 without deranging the cell or its contents, and by means of special 

 instruments it is easy, when the microscope I have devised is used, 

 and by means of a condenser of long focus, to act on the Diatoms 

 with needles or bristles, so as to render the study of them more 

 easy. 



In order to observe the multiplication of some species and 

 protect them against the lov/ering of the liquid, which may result 

 from the evaporation of the water in the cell, and to keep them 

 within the range of high-power objectives, I have adopted the 



