GENERAL METHODS. 3 



Moreover it is usually necessary to renew the culture 

 fluid in all these moist-chambers from time to time, perhaps 

 twice a day. With some larger objects this can be easily 

 accomplished by taking up the drop with filter-paper and 

 replacing it by a fresh one. 



3. In many cases one may employ with good results the 

 methods recently recommended by several writers, which 

 permit a continuous change of the culture fluid. I will de- 

 scribe in detail only the method of Klercker (II), which 

 seems to possess certain positive advantages over those of 

 Rhumbler (I) and Schonfeld (I). 



J. af Klercker uses in the first place an English slide 

 (cf. Fig. 2) to which two glass strips, L, about .14 mm. 

 thick, are cemented with Canada balsam, as shown in the 



Outlet. 



G G 



FIG. 2. Slide for culture in running water. After J. af Klercker. 



figure. In the middle of the channel thus formed is placed 

 the organism to be cultivated, and a large cover-glass is laid 

 over the whole. If the capillary space thus formed between 

 the slide, the two glass slips, and the cover is not wholly filled 

 with fluid, a sufficient quantity to fill it is added. Then a 

 strip of linen is pushed under the cover from each side (S, 

 Fig. 2), and the latter is fastened to the slide with rubber 

 bands, G. The slide thus prepared is attached to a second 

 slide with wax, in order to be more easily movable, and 

 then the whole is fastened to the stage of the microscope 

 with two clips, K, in the manner shown in Fig. 3. 



The supply of water passes through the siphon, H (Fig. 

 3), from the larger beaker (#,), which is protected from dust 

 by a glass plate, by the aid of the linen strip (5,) drawn 

 through it, whose free end lies upon the linen strip vS (Fig. 



