SPIROCHMTA BALBIANIT AND SPIROCHATA ANODONTA. 135 
films. I found it often unnecessary to add artificial media, 
hke glycerine and albumen, even after fixation, and thus 
avoided the risk, however slight, of artificial effects due to 
the added media, for these parasitic organisms are very 
small and delicate. 
Stains.—Of the various stains tried on fixed material, 
prepared as above described, the most successful results 
were obtained with alcoholic gentian-violet (Ohlmacher’s 
formula, containing a little formalin), iron-alum hematoxylin, 
Delafield’s and Ehrlich’s hematoxylins, Giemsa’s stain, and 
Billet’s modification of the latter (that is, carbonated blue 
added to azur II and eosin). Leishman’s stain was used a 
httle while in France. Alcoholic safranin and Léffler’s 
methylene blue were also good, while thionin and _ basic 
fuchsin were fairly useful. I was not very successful in my 
attempts with a dilute aqueous solution of silver nitrate. 
Tannin orange was often found most useful after Giemsa’s 
or Billet’s stains, and also on those occasions on which 
Laveran’s mixture of Borrel blue and eosin was used. ‘T'annic 
acid itself was tried to show the possible presence of flagella, 
but without result. ‘‘ Acid plasma stains,” like Orange G or 
Saurefuchsin, were found to be of little use, if not positively 
harmful, after hematoxylin. 
The most difficult structure to stain was the membrane. 
For revealing new details in this “ organella” gentian-violet 
and iron-hematoxylin were most useful, especially the former 
in the case of 8. balbianii. Heematoxylin has not, I believe, 
been used in investigating these two organisms before, though 
it gives very good results. Staining for a long period is 
necessary to show clearly the presence of the membrane, and, 
in the case of Delafield’s or Ehrlich’s hematoxylin, this is 
fortunately not accompanied by over-staining of the nucleus. 
The various modifications ef the Romanowsky coloration 
usually over-stain the internal structure of the parasite 
before staining the membrane, and the striated character 
of the membrane is seldom, if at all, clearly brought 
out by these Romanowsky stains. It is probably on 
