NOTES AND MEMORANDA. 
253 
crystals. Salicine (in balsam) gives a brilliant gold colour with 
silver points. Salicylic acid from alcohol (dry mounted) shows gold 
and green, with shades of purple and silver points. Santonin from 
chloroform (dry) shows gold and green, sometimes so blended as to 
have a truly supernal effect. Iodoform has always thrc r ' colours, red, 
gold, green, and often violet, purple, and dark gold. Chromic acid 
from absolute alcohol (dry) is the most brilliant of all. This crystal 
first takes the form of a double layer, the upper layer soon begins to 
cleave with every possible variety of line, often producing groups, 
the exquisite symmetry of which is indescribable. The surfaces of 
these lines seem to act as analyzers, and we have green, orange, and 
red presented in a brilliantly beautiful form. Crystals in plants, 
when they are in the same plane, can be well shown by this light ; 
pollens also, and stellate hairs in glycerine jelly. Very thin trans- 
verse sections of bamboo, rushes, and the like, make fine pictures. 
Anything thin enough to be illuminated without change of focus is 
not only beautiful, but the minute parts are more precisely defined 
than in any other light. The most suitable powers are half, fourth, 
or fifth inch. Precise measurements would aid but little, as stands 
and stages differ so much. Only the above general directions can be 
given. The observer must find out the exact thing by his wits, 
helped by steady nerves. The manner of forming and mounting 
such crystals as are most interesting, may now be briefly stated. 
Salicine is formed and mounted as Mr. Davies directs. Salicylic acid 
should be mounted dry, it is crystallized from common alcohol on a 
slide slightly warmed. A few seconds of sharp heat, after the drop 
has spread, and before the crystallization has proceeded farther than 
the edge, improves the forms. As soon as cool, a balsam ring is 
drawn around it ; and after a few hours, another upon the first. 
After three or four days, the cover may be put on, first slightly 
warming the latter over a lamp. In a day or two a thin coating 
of balsam is put on the edge of the cover. After a day this is re- 
peated. At the end of a week the slide may be finished with cement, 
&c. Mounted in this way are all the others, except iodoform, which 
disappears in a short time. Santonin is very permanent : also chromic 
acid. Santonin makes altogether the finest appearance from chloro- 
form, equal weight. Crystallized without heat, the effects are so 
peculiar, that there should be a slide of it prepared in that way ; heat 
to 200°, or higher, after the crystallization has gone on for a few minutes 
on a cool slide, gives a finer variety of form. Chromic acid should 
be allowed to form on a slide warmed to 90° or 100° ; then heat to 
130° or 150°. The acid should be dissolved while red, and in absolute 
alcohol, being allowed to stand half an hour or so.” 
Death of Dr. Beatty. — Our readers will be sorry to hear of the 
death of Dr. Beatty, of Baltimore, well known in connection with the 
staining of vegetable tissues. Dr. Beatty was only in his fortieth 
year, but had achieved a high reputation as a successful physician 
and microscopist. 
VOL. XVIII. 
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