ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
475 
in adding a mixture of hydrochloric acid and carbolic acid to the pepton 
bouillon which is used as a nutrient basis for the cultivations. The 
principle of the procedure rests on the supposition that certain chemical 
substances exert an unfavourable action on certain bacteria, and the 
method, like many others, is chiefly intended for the detection of 
the bacillus of typhoid fever. M. J. Wittlin is of opinion that this 
method affords but little help in the isolation of Bacillus typhosus, yet 
it is of great service in finding the various species of bacteria existing 
normally in water, as well as pathogenic organisms such as Streptococcus , 
Staphylococcus , B. coli communis , Proteus , Oidium albicans , and others. 
Urinous Substrata for Differentiating Bacillus coli communis and 
Bacillus typhi abdominalis.* — Dr. Piorkowski finds that the addition of 
urine to cultivation media facilitates the diagnosis between the bacillus 
of typhoid fever and B. coli com. Three examples are given : — (1) Urine 
bouillon. 0*5 grm. pepton are dissolved in 100 of urine; the solution 
is then filtered off into test-tubes (10 ccm. to each). These are then 
sterilised by heating them two days for 10—15 minutes. (2) Urine 
gelatin. Is made like the foregoing, save for the further addition of 
10-12 per cent, gelatin. (3) Urine agar. In this medium 2 per cent, 
agar replaces the gelatin. 
On these media the growth of B. coli was more rapid and luxuriant 
than that of B. typh. abd., the development of which seemed tardy. 
Simple Apparatus for Gathering Microscopic Objects.! — Mr. G. M. 
Hopkins describes a simple device for collecting microscopic objects. 
It consists of a tea or dessert spoon having a wire loop round the bowl, 
to which is fitted a conical bag. A piece of string is attached to the 
bottom of the bag on the outside and extends over the top and down to 
the bottom in the inside, where it is again fastened. 
In use the spoon is scraped along the surface of objects submerged 
in water, and when sufficient material has accumulated, the bag is turned 
inside out by pulling the string, and is then dipped several times into 
water in the collecting bottle. 
C2) Preparing- Objects. 
Preparation of Eggs of Toxopneustes variegatus. :£ — Prof. Wilson 
took eggs carefully selected from ripe females, fertilised them artificially 
in sea water, and preserved them at regular intervals. After testing 
many different fixing agents it was found that the best results were 
obtained by sublimate-acetic (80 parts concentrated aqueous solution of 
corrosive sublimate, and 20 parts glacial acetic acid). When properly 
used, this reagent caused no change of form or shrinkage or distortion 
of the internal structures ; the finest details are shown with a clearness 
and brilliancy which far surpasses the results of pure sublimate, or a 
number of fixing reagents.. The eggs were preserved in alcohol, im- 
bedded in paraffin, sectioned in the ‘usual manner, and stained on the 
slide by Heidenhain’s iron-haematoxylin. The best results were 
obtained with sections from 3 to 5 /x in thickness, stained 24 hours in 
* Centralbl. f. Bakterioh u. Parasitenk., l te Abt., xix. (1896) pp. 686-94. 
f The Microscope, iv. (1896) pp. 53-4. 
X See Wilson’s Atlas, ante. p. 394. 
