A Method of Sealing up Cover-glasses. 105 
conceivable that ecological adaptation may be achieved as efficiently 
by a suitable modification of the small-leaved type as by another 
kind of modification of a broad-leaved type: in fact, more than one 
kind of mechanism may be well adapted to a given set of external 
conditions. The Conifers are, however, predisposed to the adoption 
of “ architectural xerophily ” as their mode of adaptation by the 
persistent hereditary factor of microphylly. 
R. H. COMPTON. 
Cambridge, 
March , 1911. 
ON A METHOD OF SEALING UP THE COVER-GLASSES 
OF PREPARATIONS MOUNTED IN GLYCERINE. 
[Text-Fig. 15]. 
D URING a recent visit of Professor Nathorst to Cambridge, he 
brought to my notice a method of sealing up slides in which 
glycerine was used as the mountant. The method has proved so 
useful that it ought to be more widely known. It consists in the 
application of hot wax to edges of the cover-glass by means of a 
piece of thick copper wire. 
The wax was invented by Professor Lagerhein and described 
by him in the “ Botaniska Notiser ” for 1902. 1 It consists of hard 
paraffin wax (M.P. 55 n -60 n C) and mastic in equal parts. The mastic 
is powdered and cautiously heated in a porcelain dish until 
melted, when the paraffin is added in small pieces and the mixture 
stirred with a piece of wood until homogenous and free from lumps. 
Fig. 15. 
It is then poured out into a flat dish ( e.g . a Petri-dish) and when 
cool is ready for use. If desired, it may be coloured by the addition 
of some dye which will not be dissolved by the glycerine, such as 
Grubler’s “ Buttergelb.” 
The wax is applied by means of a thick copper wire, one end of 
which is fixed in a wooden handle, while the other is straightened 
and bent at right angles so as to give a straight piece just a little 
] G. Lagerheim. Metoder for pollenundersokning, p. 75, 
