92 THE AMERICAN MONTHLY [May, 
appeared as if trying to swallow it. After about a half hour the larger 
one had entirely surrounded the smaller one, which did not, however, lose 
its vitality, but did not seem to try to escape. The larger one now moved 
about with the smaller one engulphed and quiet. Finally the larger amceba 
expelled the smaller one, after which it began to expel refuse matter, or 
had anchored itself near some other refuse matter, and looked as if using 
it as a sort of grapple to rid itself of the smaller amceba. It was successful, 
and moved away, leaving the latter looking like an encysted ameeba lying 
near the little group of refuse. The smaller one, now disk-shaped, com- 
menced a contractile movement, throwing out particles or granules as if it 
were laying eggs—the particles had no regularity of shape though of approxi- 
mately the same size. After a time this ceased, and the ameba, putting out 
pseudopadia, moved in the field, leaving behind a group of the particles. 
This amceba soon lost animation, became transparent, and seemed to fade 
into a mere shell of its formerly active form. 
This observation occupied several hours, and the author suspected it of 
being a clear case of conjugation, in spite of the fact that the process had. 
never been reported before as taking place in ameeba. 
In confirmation of this suspicion it is further stated that two nights there- 
~ after the slide, which had been laid away carefully for future examination, 
was found to be full of young ameebe. They literally swarmed, and it was. 
estimated that between one and two hundred were in the slide which had 
held but two. The worn out disk was recognized and what seemed to be the 
remains of the larger amazeba.—Pvroc. Acad. Nat. Sct., Phila., 1886, p. 346. 
MICROSCOPICAL TECHNIQUE. 
Mounting opaque objects. 
By C. M. VORCE, 
CLEVELAND, OHIO. 
At page 73, of the April number of the Jowrza/, is an article under the 
above title, which, since it embraces a method of which I have had a pretty 
full experience, I think demands a word of warning. /Pasteboard or card- 
board ts not a good material for microscope slides. 1 make this assertion 
broadly, without wishing to disparage the results that some may have ob- 
tained by its use, but from the experience and observation of a quarter of a 
century of microscopical study and recreation. 
The objections I have found to it are, first, its lack of rigidity ; second, its 
lack of durability in use; and third, its lack of resistance to the effects of 
heat and moisture. About twenty years ago I was taken with a spasm of 
economy in the matter of slide materials, all of which cost then from three 
to four times what they do now, and invented the precise method described 
by Mr. Brown, which was even then not novel I found. At first the saving 
of cover glass was a great satisfaction to me. I tried all sorts of cardboard, 
strawboard, tarboard, both light and heavy, and wooden slips. I found 
the method so simple and speedy that I soon accumulated several hundred 
slides mounted in that manner. By that time trouble began to appear, and 
thereafter was never absent until a lucky accident relieved me of the whole 
collection. First, the effects of dust upon the uncovered objects became ap- 
parent, and applying a cover ¢hex would not help the case. Soon the bind- 
ing paper and edges of the slides became worn, torn, and rough, looking 
unsightly and giving no end of trouble in use. To exclude dust the slides 
