180 NOTES AND MEMORANDA. 



the layers but the outermost one are undeveloped, so that a funnel- 

 like canal is produced, separated from the exterior only by the 

 thin outer layer of the cyst ; into this canal — the " germinal pore " 

 (Keimporus) — the protoplasm extends, and after a time escapes 

 through it, by the rujiture of its thin outer covering. The process of 

 encystation takes one and a half to two hours ; the organism remains 

 encysted from two to three days. After escaping from its cyst, it is 

 slightly smaller than before. No union of different individuals into 

 a Plasmodium was observed, so that the life-history of Gloidium, as at 

 present made out, is an extremely simple one, presenting merely an 

 alternation of the free and encysted condition. 



Preparation of Microscopic Aquatic Animals. — An anonymous 

 writer in the Berlin ' Zeitschrift fiir Mikroskopie ' * gives an account 

 of a process which he has made use of for preparing slides of 

 Infusoria, Ehizopods, Daphnia, Cyclops, Algte, &c. The only success- 

 ful attempt in modern times to supply the want of such a process is 

 that of Duncker, of Bernau,t but this, for trade reasons, is kept secret. 

 The author's process, which he thinks may be identical with 

 Duncker's, is as follows : — 



By means of a pipette, some drops of the liquid, containing the 

 organisms to be mounted, are introduced into a lac cell not quite hard, 

 and covered with the covering glass. Then some drops of rectified 

 pyroligneous acid (acetum pyrolignosum rectificatum) are phaced at the 

 edge of the covering glass so as to be drawn into the cell. This 

 liquid immediately kills all the organisms without altering their 

 form. It only remains to cement the cover down in the usual way. 

 When the pyroligneous acid has become turbid, it must be filtered 

 before being used. 



With this method may be combined the staining of the objects by 

 anilin colours. Dissolve one jjart (in weight) of a solution of anilin 

 colour (the best are anilin blue or diamond fuchsin) in 200 parts of 

 distilled water ; after filtering, add 800 parts of pyroligneous acid. 

 Then with this liquid proceed as with the pure acid. After some 

 hours, the objects take a very uniform colour ; they are then mounted 

 as above, after adding a little more pure acid. If the colour is too 

 dark, it can be made lighter with acid. The author thinks that his 

 process is capable of improvement, although he has already obtained 

 excellent results from it, and he lays stress upon the facility with 

 which it can be used in travelling. 



The Postal Microscopical Society. — This Society was first 

 established in 1873, as the " Postal Micro-Cabinet Club," for the 

 purpose of affording a ready means of communication between micro- 

 scopists living not only at a distance from each other, but also from 

 London and the other large towns having Microscopical Societies. 



The Society is divided into circuits of twelve members each, 

 whose names are arranged geographically. A box of slides is sent 

 by the secretary (Mr. Alfred Allen, of Bath), at fortnightly intervals, 



* ' Zeitschrift fiir Jlikroskopie,' vol. i. (1878) p. 273. 

 t This Journal, vol. i. p. 221. 



