1887. ] MICROSCOPICAL JOURNAL. 207 
is to be made the camera can be instantly turned up in position, the focus 
corrected, and the plate exposed. The plates used measure 6 by 6.5 cm. 
Just here let it be noted that Dr. Dallinger has given his unqualified endorse- 
ment of the new oculars of Zeiss, known as compensating oculars, not only 
with the objectives of that maker, but also with objectives of English con- 
struction. This, of course, is quite apart from the use of such oculars in 
photography. Indeed, I believe that the projection oculars are not quite the 
same as those used for eye observations. 
In looking over the June number of the Journ. Royal Micr. Soc. 1 finda 
description of Schiefferdecker’s Apparatus for Marking Microscopical Ob- 
jects, which calls to mind a much simpler, but no doubt quite as efficient, 
device for the same purpose, that I have used for years. It was made, I 
believe, by Mr. May, of Philadelphia, and consists of a simple rod of brass 
about + of an inch in diameter, with a screw at the top that fits into the nose- 
piece in place of an objective. A tube fits loosely over this rod, bearing a 
diamond point below, slightly eccentric. This is turned by a milled collar, 
so as to scratch minute circles on the cover-glass. 
I know of no contribution to microscopical literature of recent date that 
equals in its far-reaching significance, as well as the industrious and continu- 
ous observation upon which it is based, the last address of Dr. Dallinger, 
President of the Royal Microscopical Society. Here we have the results of 
seven years of continuous painstaking observation, begun with a definite pur- 
pose and carried on with increasing zeal until an accident happened to the 
apparatus and put an end to the work. Already another series of the same 
kind of observations is under way. The problem set forth for solution was 
to determine the influences of changes of environment upon the life-history 
of organisms having a short period of existence, and to observe the changes 
of an adaptive character that might be induced. The investigations were 
undertaken with the monad forms, with which Dr. Dallinger is so well 
acquainted. The organisms were submitted to gradual increase of tempera- 
ture, and the effects carefully noted. Beginning at 60° F., the temperature 
was gradually raised, in the course of two months, six degrees, then two 
degrees per month, and then, when the temperature had reached 74°, the in- 
crease was very slow. At 78° the temperature remained unchanged for eight 
months, during which time an elevation of half a degree could not be sately 
borne. But, by giving sufficient time for adaptation to the changed conditions, 
the temperature was finally raised to 158°, and the organisms continued to live 
and multiply! Then the apparatus gave way, and the long experiment was 
ended. 
It. is always a source of satisfaction to find one’s own observations confirmed 
by independent workers. In 1883 it was my good fortune to trace the devel- 
opment of Ulothrix from Pleurococcus, and the results were briefly described 
in Vol. IV, p.1gt. Lately I find that Mr. de Wildeman has confirmed this, 
and that Dr. Braxton Hicks has also observed it. 
Osaka, JAPAN, Seft. 15, 1887. ( 
The meeting of the American Society of Microscopists. 
By C. M. VORCE, 
CLEVELAND, OHIO. 
The working session at Pittsburgh demonstrated the firm hold which this 
feature of the annual meeting has upon the interest of the members and the 
public. Notwithstanding the attendance at Pittsburgh was smaller than ex- 
pected, the character of the work done at the working session was fully up 
to the standard of former meetings and the interest of the members and visitors 
