282 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
acid pepsin-pepton solution, containing from 3 to 4 per cent, of nutri- 
ment, and less than 1 per cent, of NaCl. In most experiments some 
slight modification was adopted, e. g. more water, olive oil, grape sugar, 
&c., were added. In the least unsatisfactory experiment the worms 
lived from the 26th of one month to the 28th of the next. 
The great difficulty in the way of a signal success seems to have 
been the occurrence of putrefaction in the medium, which had frequently 
to be changed. 
The author thinks that the composition of the medium has less to do 
with the unfavourable results than the decomposition, since the particu- 
lar medium in which the worms survived for more than four weeks 
little resembled the conditions natural to the animal. 
It is considered that these experiments favoured the notion that 
besides requiring a suitable temperature and certain mechanical con- 
ditions, the development of tape-worms within the host is aided or pre- 
vented by the reaction of the intestinal contents, e. g. too great acidity 
being inhibitive. 
Collection and Preservation of Diatoms.* — M. J. Tempere gives 
instructions in the best mode of collecting and isolating diatoms, and 
preparing them for examination. A convenient form of pocket-drag is 
described, made of metal, which can be used for rocky bottoms or places 
encumbered with solid bodies. A list is appended of all the more 
important beds of fossil diatoms. 
(2) Preparing: Objects- 
Study of Structure of Protoplasm.! — The editor (Dr. A. C. Stokes) 
writes : — “ According to Heitzmann, Klein, and several German ob- 
servers, animal protoplasm is a network of fibrils radiating in all direc- 
tions through the cell, and containing a homogeneous fluid within its 
meshes. This and other inclosures have been referred to in an admirable 
manner by Prof. Kirsch in his valuable series on cytology ; but a 
sight of this reticulation within the cell is one that has been most 
desirable for every microscopist, but that to the amateur has been espe- 
cially difficult. The appearance of the structure has been repeatedly 
figured, but the sight of a picture is not to be compared in satisfaction 
to the sight, although it may be an imperfect one, of the object itself. 
This has heretofore not been an easy task, but through no discovery of 
my own it has recently come to my knowledge that there is a common 
animal in whose intestinal cells this structure of the protoplasm may be 
observed with comparative ease and with lively satisfaction. The animal 
is . . . Oniscus murarius. In order to see the appearances as described 
by certain observers 1 sought the Oniscus, and in five minutes had 
gathered a dozen. . . . Kill an Oniscus by a few drops of alcohol. 
Remove the legs, to get them out of the way. With fiue-bladed scissors 
slit up the body on the lower or abdominal side. Push away, or care- 
fully remove, the walls of that part of the body, and the intestine will 
be in plain sight. It is a nearly straight, tubular vessel, large for the 
size of the animal, and usually gorged with food or its remains. It is 
* Le Diatomiste, i. (1891) pp. 41-2, 4G-7, 61-1 (3 figs.), 
t Microscope, xi. (1891) pp. 276-8. 
