MOUNTING MARINE ALG. 55 
how the endochrome of certain Oscillatoracez is acted upon by 
weak syrup and by chloride of calcium solution, and it is just in 
this way that glycerine jelly and Deane’s medium act upon some 
species of marine algz. 
I have the alga Bangia fuscopurpurea mounted in two ways, 
first in balsam and again in Deane’s medium, the two appearing so 
different in character that any one not acquainted with the mode 
of mounting would have no hesitation in dubbing them as two dis- 
tinct species. Suffice it to say that the balsam mount is much 
more natural than that in Deane’s medium when compared with 
the growing plant. 
Some marine alge which I culled in 1873 in Langland’s Bay 
and Caswell Bay, at the Mumbles, near Swansea, and which were 
mounted soon after in balsam, are now (1881) as good as the day 
they were gathered, the colours being nearly as fresh. The princi- 
pal were :—Pvlota elegans, P. plumosa, Dasya coccinea, Ceramium 
rubrum, Delesserta alata, Nitophyllum punctatum, Cladophora rec- 
tangularts, C. unctalis, Bangia fusco-purpurea, and Ulva lattssima. 
‘The method I pursue is this:—The alge are first washed in 
fresh water to get rid of all sea-salts directly they are taken from 
the sea, they are then floated on to writing-paper and dried by 
gentle pressure between sheets of white blotting-paper. When 
apparently dry they are put between fresh blotting-paper and 
packed away in a dry place where they must be kept perfectly free 
from the access of light. 
When perfectly dry cut off the number of pieces required and 
soak in o/d oil of cloves for a sufficient length of time to render 
them transparent, keeping them in the dark during the whole time. 
When soaked sufficiently take them out of the oil and lay them 
upon clean white blotting-paper to absorb the excess, and mount 
in the ordinary way with cold balsam and benzol, on a cold slide, 
using a cold cover, and the result will be satisfactory. It is the 
operation of soaking the algze in turpentine and the mounting in 
warm balsam that does the mischief, and it should not be forgotten 
that if the mounted slides are constantly exposed to the light they 
will bleach in time. 
There are two points which should be noted: o/d oil of cloves 
must be used; the zezw is clear and of a very light yellow colour, 
while the old is more viscid and of a clear light brown. The other 
point is in the preparation of the balsam, that used in the foregoing 
preparations is at least thirteen years old, and most, if not all, the 
turpentine it originally contained has evaporated from it ; it has 
been solid for years. The method I adopt for bringing it into 
solution is to pour some benzo] into the jar in which it is contained, 
and when sufficient has dissolved it is poured out into the bottle 
marked balsam and benzol. By this means only a thin layer of 
