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II. — A New Groioing or Cireulation Slide. 

 By T. Charters White, M.R.C.S., F.E.M.S. 



(Read 14:ih December, 1881.) 



Inceeasing attention has of late years been devoted to tlie subject 

 of slides by which the development of microscopical organisms can 

 be observed, but the majority of the forms suggested have been 

 attended by various drawbacks and disadvantages in their design 

 and construction, leading to their disuse. The one here described 

 seems to be as efficient as can be desired ; it is, however, merely 

 put forward as a suggestion, and I do not venture to claim for it 

 more than simplicity and efficacy to recommend it to microscopical 

 observers. 



It often happens that in examining a gathering from some 

 aquatic source an organism is met with about which the observer 

 would desire to know more, but to transfer it from his slide to 

 one of the growing slides in ordinary use would probably result in 

 its loss or destruction. The slide now described is designed to 

 supersede the use of the glass slip generally used for this examina- 

 tion, so that should such an organism present itself all that is 

 required to maintain a constant current is the insertion of threads 

 of cotton into openings in the sides of the cell. The organism is 

 then duly nourished, and no alteration occurs to interfere with 

 its proper development, which can be readily noted from time to 

 time. 



The shde (Fig. 1) consists of the usual glass slip A A 

 (3 in. X 1 in.), having a narrow ledge of glass B (about |- inch 



Fig. 1. 



wide, and extending nearly its whole length), cemented to its 

 lower border with marine glue ; to this is cemented at right angles 

 a strip of thin covering glass C, about | inch wide and about 

 l^ inch from the end of the slide, having a narrow channel cut 

 through it for the passage of an intake thread D. A similar strip 



2 



