6 THE MICROSCOPE. 
eclipse of a great light in optical science. Mr. Tolles’s lofty 
character, his frankness, his honesty, his modesty and dislike for 
anything that savored in the least of boastfulness, his peculiar 
reserve and the warmth of his friendship when once the ice was 
broken, endeared him to his friends as much as his marvellous genius 
and unsurpassed skill in devising and constructing new optical 
combinations distinguished him in the world of applied optics. To 
the scientific world at large he will live as the man who dared at- 
tempt what the accepted authorities had declared to be impossible; 
as the man who not only dared to attempt, but succeeded in turning 
the “180° corner;”’ as the rare combination of artisan, artist and 
scientist whose work was not made “to sell’ only, but who, ever 
striving to surpass himself, wrought each new objective as if it were 
his only one, putting into each a portion of his own individuality 
and making a work of art rather than an article of commerce; but 
to those who knew him more intimately he will live as the shy, re- 
served but warm-hearted man of genius. Standing, as he unques- 
tionably did, at the very pinnacle of his profession, his death leaves 
a vacancy not readily filled. 
TO STAIN BACILLUS TUBERCULOSIS. 
BY T, J. BURRILL, 
HIS subject is well-nigh threadbare, but the following may be 
acceptable to many who, like myself, are interested in easy 
methods as well as in good results. 
So far as I know everyone has heretofore advised an alcoholic 
solution of the aniline dye or dies, more or less diluted with water. 
In my practice the following disadvantages and difficulties were met 
with: first, frequent failure of the stain, especially when too little 
water was used; secondly, rapid evaporation, leaving when left too 
long, a gummy mass on the dish and cover-glass hard to remove, 
and worse still a deposit of granules or little drops of aniline oil on 
the cover which no washing would remove; and thirdly, the liability 
to get one’s hands, the table, etc., tinted, as well as the organisms 
by the “running” or “creeping” tendencies of the stain. 
To avoid these and some minor perplexities many ways have 
been tried to leave the alcohol out and yet obtain a stain as good as 
