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Note on Hanging-Drop Cultivation. 

 By G. C. Karop, M.R.C.S., F.R.M.S. 



{Read March 2Ut, 1902.) 



In the course of his most interesting Presidential Address on 

 Coprophilous Fungi, Mr. Massee several times referred to cultiva- 

 tion of the spores of this group by the method of the ' hanging- 

 drop.' He appeared to take it for granted that this method was. 

 well-known to his audience at large ; and although it certainly is. 

 so to some, I am pretty confident that among the continual influx 

 of new members, many of whom are comparatively 'prentice 

 hands at microscopic biology, there are not a few practically 

 unacquainted with this simple and easy device for studying the 

 growth and development of the lower organisms, particularly 

 algae and fungi. For such alone the following brief description 

 of the affair and its handling may be useful — the more so as it is. 

 not to be found in the more elementary text-books, so far as I 

 know. The idea is to put any of these organisms in such a. 

 position, immersed in a fluid suitable for their nutrition, that 

 they may be examined for either comparatively long or inter- 

 mittent periods, with any required magnification, without being 

 disturbed, and without risk of desiccation. In such conditions, if 

 properly chosen to meet any given case, development can be 

 followed out uninterruptedly up to a certain point, and a very 

 large amount of valuable information gained at first hand on 

 growth, nuclear changes, spore formation and so foith, instead of 

 merelv takinc: book statements and their ten-times-borrowed 

 cliches for immutable truth. 



While there are several ways of contriving a * hanging-drop," 

 for the purpose of this note I shall confine myself to the form I 

 have individually found the most convenient, and which can be 

 made by any one. 



The materials required are of the simplest : some good stout 

 millboard or strawboard as used by bookbinders, 3x1 slips, 1-in. 



