Laboratory Note. 
7 1 
LABORATORY NOTE. 
A METHOD OF STAINING CYANOPHYCEyE. 
By R. C. McLean. 
f ^HE mystery which for long enwrapped the nuclear apparatus of 
the Cyanophyceae was due, in no small measure, to the 
technical difficulties involved in obtaining well stained preparations 
of the filaments for observation. The massive coat of mucilage 
which encloses many colonial species, and the sheathing cuticle of 
others absorb stain so readily and retain it so tenaciously that all 
details are obscured. Even in species where these natural 
obstructions are not present the minute size of the filaments render 
the best regressive methods, even the extremely precise Ferric- 
Haematoxylin, very difficult and tedious to carry out successfully. 
Some years ago the present writer made experiments with a 
view to finding a simple direct acting stain, suitable for the demon¬ 
stration of the Cyanophycean cell-structure. The result was that 
a method was found which gives excellent results with great ease. 
This method was partly original and partly an elaboration of one of 
the methods used by F. G. Kohl in his study “ Uber die Org. und 
Phys. der Cyanophyceenzelle ” (Jena, 1903). 
The presence and nature of the primitive form of nuclear 
apparatus found in these Algae have already been the subjects of 
several fine researches, but a great deal regarding their behaviour 
still remains to be cleared up. 
For this reason, and also because it would be desirable, where 
possible, to introduce these structures into courses on general 
Cytology, it seems worth while to draw attention to an easy method 
of preparation. The genus Oscillatoria, and in particular the species 
O. limosa, is perhaps the most favourable subject, and occurs 
constantly in aquarium jars; but practically any of the filamentous 
forms, especially those with broad cells, are suitable, although the 
form of the “ central body ” is not identical in all. 
Make up the following stain 1 :— 
Rectified Methylene Blue 1 :5000 aq. dest. 
Bismarck Brown 1 :5000 aq. dest. 
Equal quantities. The latter solution is made up by taking of the 
ordinary 1% solution in 70% alcohol 1 c.c., and adding 50 c.cs. of 
distilled water. 
1 “Rectified” Methylene Blue is that prepared specially for ultra vitam 
staining. It may be obtained from any of the agents of Griibler & Co., 
and is preferable to the ordinary compound for the above purpose. 
