^K'nli. S?rS:T ^oyal Microscopical Society, 127 
quite as readily extracted without resorting to this process ; another 
advantage is gained, inasmuch as clear transparent fluids are ob- 
tained without incurring loss by filtering through blotting-paper. 
Occasionally it is seen that spirits affect results, by the extraction 
of the gum resin and essential oil of the flower along with the 
colour ; but this is not a very grave evil, nor does it appear to be 
necessary to strain away the pollen grains, which are at times sus- 
pended in considerable quantities ; indeed, this will be found to 
be an excellent way of collecting and preserving the pollens for 
microscopical examination. A little pure simple syrup should be 
added to the solutions before the tubes are filled and hermetically 
sealed. 
The pure vegetable and animal oils, which in themselves 
produce no reaction on the spectrum, may in some instances be 
employed with advantage for the extraction and preparation of 
colouring matters. The fine colour of Anchusa tinctoria (Alkanet- 
root) is readily extracted by any kind of oil ; in this menstruum it 
becomes a fixed colour, and a much finer series of spectrum bands 
are obtained. An oil that in no way afi'ects the spectrum, as ex- 
pressed castor-oil, or purified cod-liver oil, should be employed 
for the purpose of dissolving out the colour of alkanet-root. A 
good almond-oil coloured pink by alkanet-root gives a fourth and 
fifth band in the blue and violet. It is curious to watch the re- 
actions produced in the spectrum by the combination of various 
fixed oils with this colouring matter ; with ordinary flask olive-oil, 
the chlorophyll band of the oil itself seen in the red is exaggerated, 
as well as the second band in the blue, and the violet is wholly 
absorbed; castor-oil gives an extra band in the indigo; cod-liver 
oil augments the blue end of the spectrum, and develops a third 
band in the blue. The vaunted Macassar-oil, supposed to be 
prepared from roses, evidently owes its colour to alkanet-root, as it 
produces the same series of bands as are produced by alkanet-root 
in olive-oil. When to a small quantity of spirituous solution of 
alkanet-root lime-water is added, it changes to purple-pink, or 
red ; the absorption bands are well marked, especially those between 
C and D, and I) and E ; but the lines do not appear exactly in the 
same portion of the spectrum indicated by Mr. Sorby in his ex- 
periment with carbonate of soda. This solution, like his however, 
is not permanent, and with the change of colour the absorption 
bands disappear. If to a pink-coloured spirituous solution simple 
syrup is added, the red end of the spectrum is greatly augmented ; 
the two bands in the green are sharply defined, and that in the 
blue is wider, while the violet is completely absorbed. Although 
the sugar crystallizes out and falls to the bottom, the colour does 
not fade. A solution of a bright pink appears to be the best tint 
for observing the reactions of the anchusa-root, and the employ- 
