wh. THE AMERICAN MONTHLY [Mar 
into a number of portions, with subsequent destructiun of 
the identity of the wood elements. Later, the quiescent 
cambium, lying between the original internal phloem and 
the axial woody ring, takes upon itself new growth, and 
proceeds to lay down xylem on the one side and phloem 
on the other. 
THE ARRANGEMENT OF CILIA ON PARAMECIUM.—The 
same journal contains a note on staining the cilia of Par- 
amecium, which, in common with many others of the In- 
fusoria, are so fine and closely set as to make it difficult to 
determine their exact arrangement even by the most care- 
ful focussing. A drop of Loffler’s alkaline methylene-blue 
is mixed with a drop of water, in which the animaleules 
are swimming on the slide, and the cover-glass placed in 
position. Intra vitam staining takes place in many of the’ 
individuals ; but they soon die, and the cuticle separates. 
more or less completely from the cytoplasm and forms a, — 
halo round the deeply stained body. The perforations in 
the cuticle are thus brought very distinctly into view and 
the plan of arrangement of the cilia revealed. The stain: 
is prepared as follows: Add 30 c.c. of a concentrated al- 
coholic (95 per ct.) solution of methylene-blue to 100 c.c. 
of a ‘0001 solution of caustic potash. The caustic potash 
solution may be prepared by adding 1 c.c. of al per cent. 
solution of potash to 100 c¢.c. of distilled water. 
New OBJECTIVES BY OTTo HIMMLER.—By the courtesy 
of Messrs. W. Watson & Sons, of High Holborn, London, 
we have recently had an opportunity of examining two 
objectives by a comparatively new maker, Mr. Otto Him- 
miler, of 9 Brandenburgstrasse, Berlin, that deserve more 
than passing notice. They were styled semi-apochromats, 
which implies only, we presume, that in them the newer 
Jena glasses have been used. Their corrections were ex- 
ceptionally good, and showed once more how near the best 
and newest achromatic lenses come to the more costly 
