232 
The President of the Section, Mr. Sidebotham, then read 
a paper on mounting objects for the microscope in fluid. 
The paper referred chiefly to the mounting of Desmidiacese 
and other freshwater algse. Mr. Sidebotham recommended 
a cell of japan black, the covering glass fastened on with gold 
size, then a coating of lac varnish, and afterwards several 
coatings of japan black, applied each when the previous coat- 
ing was dry. 
Mr. Sidebotham exhibited Desmidiacese, &c., mounted by 
himself in the years 1842 to 1847, in various fluids, and 
concluded that for this class of objects water was the best 
medium, the specimens mounted in 1842 being as perfect in 
structure and colour as when first prepared. Many specimens 
had become spoiled owing to the air penetrating into the 
cells, from the cracking of the varnish, but Avith care and a 
coating of lac varnish before the japan black he thought this 
would in future be of rare occurrence. 
Mr. Sidebotham then explained a plan of mounting dia- 
tomaceae in balsam, so as to preserve their forms and colours, 
and also keep the frustules attached to each other. 
Professor Williamson corroborated Mr. Sidebotham’s 
experience as to Avater being the best medium for the Des- 
midiacese ; those specimens mounted by himself more than 
tAventy years ago, Avhere the fluid had been preserved, were 
as perfect as Avhen first prepared. 
Mr. Danceb mentioned that he had specimens of Volvox 
globator mounted in Avater in the year 1 843 by himself, quite 
perfect in form and colour ; he preferred gold size as a material 
for cells to japan black. 
Mr. Nevill exhibited the larva of a gnat mounted in 
Avater four years ago, shoAving that this mode of preparation 
is applicable to animal as Avell as vegetable structures. 
