Laboratory Notes. 
123 
never holozoic. Pascher has shown, however, that although starch 
is formed in 'certain Cryptomonads ( Cryptomonas erosa, 
Chroonionas baltica, Chrysidella, Chilomonas ), this is not the case 
in other forms which have been investigated (Protochrysis, 
Cryptochrysis, Chroonionas Nordstedtii) nor in the Phaeocapascae, 
where the assimilate is either leucosin or oil. All that can be said 
on this head is that solid assimilation products are relatively rare 
in the Chrysomonads and relatively common in the Cryptomonads. 
Again, the beginnings of the characteristic furrow of the 
Cryptomonads are seen in the Ochromonadales, and even in the 
Chromulinales, where the anterior end of the body shows a pit in 
which the flagellum is inserted. 
(To be continued). 
LABORATORY NOTES. 
Method of Double-staining Microtomed Sections in the Ribbon. 
In the course of an investigation on the anatomy of the rhizome of Statice 
Limonium, considerable difficulty was experienced owingtothe fact that though 
the tissues embedded well in paraffin, and cut easily, immersion in xylol for 
the removal of the wax immediately washed the sections from the slide This 
was probably due to the fact that the periphery of the sections is occupied by 
a well developed cork layer which adheres imperfectly to the slide (although the 
egg-albumen was known to be in good condition), and tends to separate from 
it even during the drying process following on the floating-out of the ribbon 
in water. As it was necessary^ to obtain serial sections, various experiments 
were tried based on the methods described by T. G. Hill,' and the following 
are the chief results obtained. 
Method I. Sections which show a tendency to ivasli off the slide, e.g., Statice 
Limonium rhizome. 
The ribbon is floated out on the prepared slip with Delafield’s Haematoxylin, 2 
the slip is warmed until the sections are quite flat and the superfluous stain is 
then drained back into the bottle. The Hsematoxylin is replaced by a saturated 
solution of Safranin in 50% alcohol, care being taken that the stain flows 
under the ribbon and not over it; after a few minutes the stain is drained off, 
the sections are “ blotted down ” with hard smooth blotting paper, and the 
slide is allowed to dry either by exposure to air or by warming. The prepar¬ 
ation is completed, without removal of the paraffin, by mounting in rather liquid 
Canada balsam. 
If a single stain is sufficient, either Safranin or Gentian Violet gives 
excellent results, since the tissues are stained generally. 
1. A method of Staining Microtomed Sections in the Ribbon. New l J hyt. Vol. xi, No. 2, 
Feb. 1912. 
2. Ehrlich’s Haematoxylin gives very poor results, and Mr. Hill informed me that this was 
the formula he used. 
