274 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
ment is as seen in the illustration. The filter is placed in a test-tube 
D, and the air therefrom is exhausted by means of an air-pump. Hence 
the fluid to be filtered flows from the flask G, through L) and C to H. 
Between the bottom of the porcelain filter and the test-tube, a piece of 
cotton-wool is placed. 
Apparatus for cultivating Anaerobic Microbes.*— Dr. C. Brantz 
has invented an apparatus for the better cultivation of anaerobic micro- 
organisms. The apparatus, which is depicted but not described, con- 
sists of a holder or receiver for the solution of pyrogallic acid. It is 
placed beneath the slide and has two apertures, one of which opens 
into the chamber where the organisms are being cultivated in hanging 
drops, while the other is for connection by means of a caoutchouc tube 
with an apparatus for developing hydrogen gas. The receiver is capable 
of containing 5 grm. of the pyrogallic acid solution. 
(2) Preparing Objects. 
Method of investigating Development of Limax maximus. + — 
Miss Annie P. Henchman found that the best way of obtaining embryos 
was to keep adults, say twenty-five or thirty, in a large tin pail, the cover 
of which was perforated with small holes. It is best to feed them on 
cabbage, which affords them a sufficient protection against desiccation, 
and a place where they may lay their eggs. Care must be taken to keep 
the vessel clean. Eggs were generally found in the morning, in bunches 
of from thirty to forty. As they are more abundant in the early stages 
of confinement, it is better to obtain a few slugs often than many at 
once. The eggs must be carefully protected from drying. In a 
moderately warm room hatching occurs between the twenty-second and 
the twenty-seventh day. 
The best agents for killing embryos are either 0*33 per cent, 
chromic acid or Perenyi’s fluid. The chromic material, when well 
stained with alcoholic borax-carmine, shows the differentiation of nerve- 
cells and nuclei excellently. Good results fcr the study of cell-division 
have also been obtained by staining with Czokor’s cochineal. Picro- 
carminate of lithium is valuable in later stages, as it brings out nerve- 
fibres, which are stained yellow, while the ganglionic cells are coloured 
red. 
It is best to remove only the outer envelope before killing the 
embryos, as they are thus less likely to be injured. The inner mem- 
brane may be removed with needles after the eggs have been dropped 
into water to which a few drops of acid have been added. The embryos 
■will be found to be very delicate, and must be handled with great care 
through every step of the process. Miss Henchman employed only the 
chloroform method of imbedding in paraffin. The embryo should be 
carried through the period of heating as quickly as possible, for the 
embryos are very apt to become brittle if subjected to the heat too long. 
They should be imbedded within an hour, or an hour and a half, from 
the time they are first put upon the bath in the chloroform. Paraffin 
* C’entralbl. f. Bakteriol. u. Parasitenk , viii. (1800) pp. 520-1 (1 fig.), 
t Bull. Mus. Comp. Zool., xx. (1800) j p. 171-5. 
