604 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
bacterial origin, all stages of conversion of the bacteria into granules 
being demonstrable. 
New Methylen-blue Method.* — Herr A. Betbe has hit upon ammo- 
nium molybdate as a suitable substance to combine with the tetra- 
methyldiamidothiodiphenylamin of methylen-blue in order to obtain a 
less soluble salt than in the ordinary method. Moreover, hyperosmic 
acid acting on the methylen-blue molybdate in the presence of excess 
of ammonium molybdate forms a combination darker blue in colour, 
insoluble in alcohol even after weeks, and with other advantages. For 
Vertebrates, Bethe recommends the following mixture : — Ammonia 
molybdate 1 gr., distilled water 10 ccm., peroxide of hydrogen 1 ccm. ; 
hydrochloric acid 1 drop ; for Invertebrates, half the quantity of 
peroxide of hydrogen, and no hydrochloric acid. He gives full details 
as to the employment of his new method, which has yielded highly 
satisfactory results. 
Modification of Gram’s Method : Staining with Thionin.f — After 
pointing out that the staining of microbes is effected indirectly, as by the 
Ehrlich and Gram methods, and directly, as by the methylen-blue, with 
tannin and other methods, M. Nicolle describes a modification of Gram 
for which the following reagents are necessary: — 
Gentian-violet. — Saturated solution of gentian-violet in 95° alcohol, 
10 ccm. ; 1 per cent, phenol in H 2 0, 100 ccm. 
Eosin. — Saturated solution of eosin in 95° alcohol, 50 ccm. ; alcohol 
95°, 100 ccm. 
Fuchsin. — Saturated solution of fuchsin in 95° alcohol, 5 ccm. ; 
H 2 0, 100 ccm. 
Orth’s Carmine. — To the carmine one-sixth alcohol at 95° is added in 
order to prevent the sections from becoming separated from the slide. 
Picric Acid Alcohol. — Just sufficient picric acid is added to 95° spirit 
as will impart a very pale yellowish tint. 
Gram’s Iodine. — Iodine, 1 grm. ; iodide of potassium, 2 grm. ; H 2 0, 
200 grm. 
Absolute alcohol to which one-third and one-sixth of aceton have 
been added. 
Absolute alcohol. 
Alcohol at 95°. 
Alcohol and ether in equal parts. 
Xylol. Xylol balsam. 
To stain cover-glass preparations of a culture, the film is fixed in 
alcohol-ether and then treated for 4-6 seconds with the phenol gentian- 
violet, after which it is immersed in the iodine, renewed once or twice, 
and next placed in the one-third alcohol-accton. 
If a pathological product, it may be double-stained by passing the 
cover-glass through the eosin solution after decolorising in alcohol- 
aceton. Should the pathological product contain an organism stainable 
by Gram and another decolorised thereby, the alcoholic solution of 
fuchsin should be used instead of the eosin. 
Sections may be triple- stained by combining the action of carmine, 
* Arch. f. Mikr. Anat., xliv. (1895) pp. 579-622 (3 pis.), 
f Ann. Inst. Pasteur, ix. (1895) pp. 664-70. 
