372 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
In 36-48 hours it is neutralised, sterilised, and filtered through 
paper. The reaction should be about neutral to litmus paper, and 5 com. 
of the peptonised milk should, with phenolphthalein as indicator, corre- 
spond to 1-2 ccm. of 1/10 normal soda solution. It is advisable to take 
the amphoteric reaction of milk into consideration, otherwise the pep- 
tonised milk may be too acid. 
If the milk be cloudy it may be cleared by boiling with white of egg 
and filtering. Gelatin or agar is to be added after the first filtra- 
tion. 
(2) Preparing- Objects. 
Demonstrating the Tubercle Bacillus in Tissues.* — Dr. G. d’Arrigo 
and Dr. E. Stampacchia recommend as fixatives of tissues to be examined 
for tubercle bacilli the two following solutions. 
Pyrogallic acid 2 grm., alcohol (95 per cent.) 100 ccm. The 
solution must be freshly made as occasion requires, and the pieces, 
having been first washed in water, are immersed therein for four days. 
The solution is better renewed at the end of two days. After removal 
the pieces are transferred to 95 per cent, alcohol (changed every 5-6 
days) until it is no longer blackened. 
The second solution recommended is Hayem’s fluid, which is com- 
posed of distilled water 100 grm., sodium chloride 0 • 5 grm., sodium 
sulphate 2*5 grm., sublimate 0*25 grm. The pieces, which must be 
small, are left in this solution for 24 hours, and kept in the ther- 
mostat at 37°. After removal they are washed in running water for 
some hours, and then transferred to alcohol to which a little iodine has 
been added. 
The sections are obtained by the paraffin procedure, and are made to 
adhere to the slide by the distilled water and heat method. The stain- 
ing solutions recommended are the Ziehl-Neelsen phenol-fuchsin, fol- 
lowed by Gabbet’s methylen-blue, the formula for which is, distilled 
water 100 ccm., sulphuric acid 50 ccm., methylen-blue 2 grm. 
It is advisable to allow the phenol-fuchsin solution to act for 20-30 
minutes at a temperature of 40°. The preparation should next be 
washed in a mixture of spirit and water until the stain is no longer 
given off, after which it is treated with the methylen-blue solution for a 
few seconds only. The preparation is then washed in water, which is 
changed until it is no longer stained, and finally mounted in the usual 
way. 
In the case of sputum, especially when this secretion contains few 
bacilli, it is advised to mix some with 1/3 alcohol and heat the test-tube 
in a thermostat for 24 hours at 37°, or for three hours at 50°. The 
mixture should be frequently stirred up in order to allow the spirit to 
thoroughly penetrate the sputum. Prepared in this way, sputum will 
keep for a long time, and bacilli can be demonstrated therein after months 
and even years. 
Demonstrating the Structure of Coli and Typhoid Bacilli.t — Dr. A. 
Wagner has demonstrated the structure of coli and typhoid bacteria by 
the following method. In 100 grm. of a boiling 1/4 per cent, salt 
* Centralbl. Bakt. u. Par., l te Abt., xxiii. (1898) pp. 61-7, 123-31. 
f Tom. cit., pp. 433-6, 489-92 (2 pis.). 
