484 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Kiefe e — Z ur Kultur des Gonococcus Neisser. (Cultivation of G. neisseri .) 
Berl. Klin. Wochenschr., 1895, pp. 332-4. 
Novy, F. C. — Directions for Laboratory Works in Bacteriology, for tbe use of tbe 
Medical Class in the University of Michigan. Ann Arbor, 1894, 8vo, 209 pp. 
Van Ermengem, E., & E. Sugg — Recherches sur la valeur de la formaline a, 
titre de disinfectant. (The Value of Formalin as Disinfectant.) 
Arch, de Pharmacodynamie, I. fasc. 2, 3. 
Whipple, Gr. C. — A Standard Unit of Size for Micro-organisms. 
Amer. Mon. Micr. Journ ., 1894, pp. 377-81. 
(2) Preparing- Objects. 
New Method of Studying Cell Motion.* — Dr. C. Lennard describes 
a method of studying cell motion which consists in the making of a 
consecutive series of instantaneous photomicrographs of the same 
microscopic field taken at definite intervals, and the comparative study 
of the series. The author’s first series exhibits the amoeboid motion of 
the white blood-corpuscles, and the change in shape and motion with 
relation to the surrounding stationary and identical folds is well marked. 
The second series shows the path of the white blood-corpuscle in forcing 
its way through a mass of red adherent blood-corpuscles. The third 
series is said to be of marked interest, a white has seized on a red cor- 
puscle, and a series of photomicrographs shows that it has dragged it 
through a considerable distance in a field which is proved to be statio- 
nary and identical in all the photomicrographs. The fourth series 
shows motion in a red blood-corpuscle; the fifth and sixth show the 
passage of the red blood-corpuscle from a capillary in which blood is 
in motion, and from one in which the blood is at rest. The seventh 
series shows a capillary ; along the inner surface of the wall of this 
there may be seen white corpuscles in which the series indicates 
movement. 
Experiments on Frogs’ Eggs.f — Mr. T. H. Morgan, in his experi- 
ments on the blastomeres of the Frog’s egg, followed in general the 
directions given by Roux, but some eggs were turned after the operation 
so that the white pole was upwards. As the membrane was pierced, 
the egg could easily be turned into any desired position, and it would, 
in most cases, hold this position until subsequent cleavages had taken 
place. The eggs after the operation were placed on a piece of moistened 
glass and kept for ten hours under a bell-jar in a saturated atmosphere. 
If, immediately after the operation, the eggs be simply thrown into a 
dish of water, they assume all possible positions with respect to the 
vertical, and tend to hold that position through subsequent stages of 
development. 
Study of Necturus maculatus.J — Mr. B. F. Kingsbury, in his 
examination of the histological structure of the intestine of this Amphi- 
bian, found that the best way to harden the tissues was to use mercuric 
chloride, picric alcohol, or Ehrlich’s fluid. The first of these was made 
by adding a saturated solution of mercuric chloride to normal salt 
solution. The tissue was hardened in this for 1-12 hours and then 
* Proc. Acad. Nat. Sci. Philad., 1895, pp. 38 and 9. 
f Anat. Anzeig., x. (1895) pp. 623 and 4. 
X Proc. Amer. Micr. Soc., xvi. (1894) pp. 43-5. 
