4 
obtained by the use of a number of stains, I am satisfied that 
hematoxylin counter-stained with Bismarck-brown is the best 
-all-round combination. It is unsurpassed if the sections have 
to be photographed ; while it is more restful to the eye when 
a large series of sections have to be examined than are most 
colours. I have also used hematoxylin along with saffranin and 
obtained good photographs. 
Photographing the sections.—In my opinion the flame of an 
oil lamp is preferable as a source of illumination to more powerful 
methods of lighting such as acetylen and incandescent gas. 
For the best results the condenser should be achromatised and 
fitted with an iris diaphragm. Strangely enough, contrary to 
the published experience of most workers, I have obtained 
better photographs without the use of an eyepiece than with 
one, even when using a_ specially constructed projection- 
eyepiece and making all adjustments most carefully. Backed 
orthochromatic plates give in most cases the best results, and 
when the sections have been stained with Bismarck-brown no 
light-filter is necessary. In every case the magnification in 
diameters was carefully ascertained at the time of taking the 
photograph 
Many workers find it difficult to obtain sufficient density in 
their negatives without having recourse to intensification. The 
best all-round developer I am aware of is one in which the re- 
ducing agent is a mixture of metol and hydroquinone in the 
proportion 1:2; the accelerator being sodium hydrate solution 
to which a little citric acid is added to prevent stain. 
In conclusion I desire to state that I have carried out this 
investigation, first, as a Carnegie research scholar, lateras a Carnegie 
research fellow, at the Royal Botanic Garden, Edinburgh. My 
grateful thanks are therefore due to the Carnegie Trust for the 
Universities of Scotland ; as well as to Professor Bayley Balfour, 
under whose supervision I have worked, for kind assistance in 
many ways, and for supplying me with seed of many plants, 
some of considerable rarity. 
I, THE GENUS ASPARAGUS. 
With the exception of Asparagus medcoloides, Thunb.—merely 
mentioned by Klebs (4) in a list of those monocotyledons having 
a type of germination which he terms “‘ type 1 ’—the only member 
of this genus whose embryo and seedling have been even super- 
ficially described appears to be A. officinalis, Linn. This is the 
