2(32 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Investigation of Freshwater Dendrocoela.* — M. G. D. Chichkoff 
finds that the best fluid for killing these worms is one containing 2 per 
cent, bichloride of mercury, 6 parts; 15 per cent, acetic acid, 4 parts; 
pure nitric acid, 2 parts ; 14 per cent, chloride of sodium, 8 parts ; and 
2 per cent, alum, 1 part. Put some of the fluid in a watch-glass or 
porcelain dish, take a worm on a spatula in a drop of water, and when it 
begins to move tip it into the fluid. The animal will die at once, with- 
out any contraction. After the worm has been in the fluid for one or 
two hours put it into 70 per cent, iodized alcohol to remove every trace 
of the bichloride of mercury ; after passing through 80 per cent., 90 per 
cent., and absolute alcohol, the worm will be ready to be stained. For 
this purpose boracic carmine was successfully used. Chloroform for ten 
minutes was used to clear the tissues. The author has observed that if 
specimens are left for more than twenty minutes in paraffin they cannot 
be used for sections, as they become brittle, and their histological 
elements are seriously displaced. 
By means of Schanze’s microtome sections 1/100 to 2/100 mm. thick 
were obtained, and were fixed to the slide by Schaellibaum’s collodion. 
The author claims many advantages for the above method ; cilia are 
perfectly preserved, and epithelial cells are in no way disarranged. In 
preparations which were to be teased Muller’s fluid was used, and was 
followed by 3 per cent, acetic acid mixed with a few drops of 10 per 
cent, nitric acid. Teasing is effected in slightly acid glycerin. The 
isolated parts may be stained by haematoxylin or Beale’s mixture of 
carmine and glycerin. 
The cellular structure of the epithelium of the pharynx was demon- 
strated by treatment with a 1/400 solution of nitrate of silver, into which 
the isolated pharynx was plunged. 
Killing and Preserving Rotatoria. | — Mr. C. Rousselet has worked 
out a successful method of killing and preserving Rotifers in their natural 
extended state. It consists in narcotizing the animals by adding a small 
quantity of a 2 per cent, solution of hydrochlorate of cocain to the water 
in a trough, and when the Rotifers are sufficiently weakened, they are 
rapidly killed and fixed by adding Flemming’s chromo-aceto-osmic acid 
solution ; then, in half an hour, washed in distilled water and put up in 
an aqueous preservative fluid. The action of cocain is not the same with 
different species of Rotifers, and therefore the length of time the animals 
have to remain under the influence of the anaesthetic varies greatly in 
different species. Distilled water, with only a trace of the fixing solution 
added, is recommended as the best preservative fluid. Single animals 
as well as large numbers can be treated at the same time. Rotifers pre- 
pared in this way are fully extended, nearly as transparent as in life, 
with the cilia, muscles, nerve-threads, and all minute anatomical details 
fully preserved. 
Demonstration of Parasitic Protozoa in Cancerous Tumours.J — 
Dr. M. Armand Ruffer and Mr. J. H. Walker fixed their material with 
absolute alcohol, concentrated sublimate solution, or (small pieces) 
* Arch, de Biol., xii. (1892) pp. 438-41. 
t Journ. Quekett Micr. Club, v. (1893) pp. 205-9. 
X Journ. ol Pathol, and Bacteriol., 1892. 
