OF THE STIPiTATE DIATOMACE^E. 
85 
Fig. 43. 
tlie unavoidable removals from the herbarium, or from any 
accident to the papers in which they are contained. The 
safety of the Diatomacese is best 
secured by making the envelope 
of the form annexed, fig. 48. The 
slide with its deposit is laid on 
the square, b , face upwards. The 
upper square, a, is carefully folded 
over it, and the double square 
thus formed is again folded over 
the lowest part, c. The two wings, 
d , e , being successively bent over 
the whole, prevent the glass from 
falling out at the sides. 
Should the plants be of a pecu- 
liarly delicate nature (as is gene- i 
rally the case where they have 
been subjected to the action of an acid), it is a good plan to 
gum a strip of cardboard on each side of the central mass, 
a, bj fig. 44. Upon these a loose piece of glass may be laid 
whenever the specimens are put away, which may be taken 
Fig. 44. 
off when the latter are required for examination. I am not 
sure that this arrangement of the covering glass had not 
better be the general rule with beginners, instead of the 
exception, because it ensures the safe keeping of the en- 
closed Algse. 
