238 Tue Microscope. 
degree on the scale being two centimetres in length and divided 
into tenths. The bore and length are so arranged as to bring 
that part of the scale near 30° on a level with the eye of the 
eye-piece, in order to facilitate quick readings without moving 
the head. The box serves as a water bath in which any ob- 
jective from one-half to one-tenth may be immersed without se- 
rious loss to the objective’s optical capacity. The critical point 
of the fluid may be readily determined in ten minutes by both 
the disappearance and reappearance of the bubble within a 
twentieth of a degree. 
Prof. Henry F. Osborn’s paper upon a microscopic method 
of studying the amphibian brain was valuable. The brain is 
hardened in “ Miller’s fluid,” the ventricles being fully injected. 
After the usual alcoholic treatment, the brain is placed for one 
week in a carmine solution, then for twenty-four hours in acetic 
acid. The embedding mass is prepared by shaking the contents 
of an egg with three drops of glycerine. After soaking in this 
mass, the brain is placed in this position and hardened in the 
vapor of boiling eighty per cent. alcohol. The mass is then 
placed for one week in absolute alcohol. Serial sections are 
then made under alcohol with a microtome. The sections are 
then arranged on the slide and covered with blotting paper, 
and treated with alcohol and oil of cloves through the blotting 
paper. 
Dr. H. G. Beyer reported one of his observations made dur- 
ing his still uncompleted researches on Lingula. In his abstract 
he says: ‘One ot the points that I should like to demonstrate 
from one of my sections is a probable communication of the so- 
called segmental tubes with one of the diverticula (liver) of the 
alimentary canal of the animal, by means of a convoluted 
tubule.” 
Dr. R. H. Ward described a couple of neat contrivances— 
one, a new illuminating arrangement called the iris illumina- 
tor; the other a long-armed lens-holder. Professor William A. 
Rogers gave a description of the various steps by which a centi- 
metre or an inch may be produced from a standard metre or a 
standard yard respectively. 
The iast two have already been noticed in the report of the 
American Society of Microscopists. 
