THE MICROSCOPE. 159 
T also looked at the same rulings with the aid of an Abbé con- 
densor, but I could not resolve any lines in bands containing more 
than 200,000 lines to the inch. 
Signed by F'reperick Nevporr, JR., 
Wm. Heapiam, Jr., Witness. H. J. Gross. 
Hawk’s Park, Fla., April 18, 1889. 
Eprror Microscope: 
I wish to add a small tribute to the memory of Henry Mills, 
the notice of whose death appears in the March number of your 
journal. 
I never had the pleasure of meeting Mr. Mills face to face, but 
have had more or less correspondence with him for several years 
past, and I am one of those who have received many benefits by his 
kind words, and can fully appreciate all that was written of him by 
Prof. Kellicott. 
Mr. Mills wrote me in January of his intention to come to 
Florida this winter, and expressed a desire to visit me at my home, 
but the anticipations of the pleasure of his company were not 
realized, for my letter in reply was never seen by him. In a few 
days after I received a letter from his daughter, Mrs. R. B. Richard- 
son, informing me that her father had gone to “ a brighter world, a 
a place more congenial than the sunny South.” 
Accompanying Mr. Mills’ last letter to me was a vial of diatoms, 
which I have no doubt was one of the last, if not the last, specimen 
ever sent out by him. EK. 8S. Conrant. 
10. (Ans.)—Glycerin jelly is best for mounting stained wood 
sections. Anything to be mounted in balsam must be dehydrated; 
this shrinks the protoplasm and leaves the section mummyfied. 
Glycerin jelly preserves the protoplasm and differentiates structure 
perfectly. It preserves colors better than balsam. 
dD: SB 
I have used balsam, glycerin jelly and glycerin for mounting 
both stained and unstained wood sections. The balsam mounts 
bring out detail that I fail to find in either of the others. This is 
especially true of the stained sections, and I find that it will do to 
stain the tissues much deeper for balsam than for glycerin or 
glycerin jelly. A ring of gold size around the balsam mount will 
prevent it from becoming so dry and brittle that the cover glass will 
crack off. Such a protection also has a tendency to prevent the 
balsam from turning yellow, as we sometimes see it do in very old 
mounts. W. M. WHELPLEY. 
