100 THE AMERICAN MONTHLY. [May. 
preparation being completed when the solution is removed from the cell by the blot- 
ting paper. 
If the crystallization of the silver be unsatisfactory, the cell may be readily cleaned 
and another layer of wax applied. In order to apply the wax to the cell, a sheet is 
placed on the cell, pressed slightly with the finger, and a disk of the wax forced into 
the said cell by means of a cork that will snugly fit it, sufficient pressure being applied 
to cause the wax to adhere to the glass slide or to the wax already in the cell. 
There seems to be no rule by which the deposition of the crystals can be regulated, 
as under apparently the same conditions one preparation will be successful and the 
next one will be a failure. 
It would seem that a small quantity of gum in the solution would cause the crystals 
to adhere, and prevent them from breaking or shaking loose when the slide is handled 
roughly. Gum arabic has been tried without success, as it causes the crystals to turn 
black. 
HowevVer, the crystals usually adhere firmly enough to the cell and to each other to 
stand all ordinary usage. 
A greater mass of crystals may be obtained by repeating the deposition in the same 
cell, and allowing one mass of crystals to form on top of the other. 
When forming in the solution, the crystals seem to almost completely fill-the cell, 
standing out laterally, but when the fluid is removed they fall to the bottom and appear 
to the eye to form a thin layer, but under the microscope they stand out in bold relief. 
Dr. Caldwell showed a ‘bolus,’ one of about a peck, recently removed from the 
colon of a horse that died of peritonitis. The mass was about two inches in diameter, 
of a brownish color, and showed facets where it had been impacted against neighbor- 
ing masses. The mass was yielding to the touch, and was of a soft feeling like felt. 
Microscopical examination showed it to be composed principally of hairs, with traces 
of calcareous matter. Upon examination of the specimen, Dr. Taylor thought the 
whole thing was composed of ‘ vegetable hairs,’ and thought it had resulted from eat- 
ing some kind of feed containing the hairs. He thought it would be interesting to 
examine some of the feed to which the horse had been accustomed. 
Dr. Schaeffer showed several masses about the size of a filbert which had been sub- 
mitted to him for examination by a physician who stated that they were from a patient 
of his who told him that she coughed them up, and also passed them from her 
bladder and rectum. Microscopical examination showed the masses to be composed 
entirely of lung tissue. 
E. A. BALLocH, Rec. Seer. 
Exchanges. 
{ Exchanges are inserted in this column without charge. They will be strictly limited to mounted objects, and 
material for mounting. ] 
Diatoms Synedra superba in situ upon alga (Ceramium pede aan exchange for good mounted slides. in 
animal histology. ENRY L. OSBORN, Lafayette. Ind. 
Wanted, earths, recent diatoms, and miscellaneous objects for mounting. Only first-class material offered or 
desired. M. A. BOOTH, Longmeadow, Mass. 
Wanted, exchange of slides, and correspondence on unusual urinary products. 
J. M. ADAMS, Watertown, N. Y. 
Ten selections of cleaned Marine Gulf Diatoms, and 100 lbs. Gulf Marine Diatom Muds. Correspondence 
invited from any one. : K. M. CUNNINGHAM, 
Land Office M. & O. R.R. Co., Mobile, Ala. 
Pathological and Histological Slides (very fine) in exchange for other good slides. 
F. M. HOYT, 160 Washington Park, Brooklyn, N. Y. * 
Correspondence with animal histologists with regard to exchanges solicited. 
HENRY L. OSBORN, Lafayette, Ind. 
Publisher’s Notices.—All communications, exchanges, etc., should be addressed to Henry Leslie 
Osborn, Lafayette, Indiana, Purdue University. 
Subscriptions, and all matters of business, should be addressed to the Business Manager, P. O. Box 
630, Washington, D. C. ‘The address of Mr, R. Hitchcock is Osaka, Japan. 
Subscription price $1.00 PER YEAR strictly in advance. All subscriptions begin with the Fanuary 
number. A pink wrapper indicates that the subscrip.sion has expired. 
Remittances should be made by postal notes, money orders, or by money sent in registered letters. Drafts 
should be made payable in Washington, New York, Boston, or Philadelphia, to the order of the Business 
Manager. The regular receipt of the JouRNAL, which is issued on the 15th of each month, will be an acknowl- 
edgment of payment. 
The first volume, 1880, is entirely out of print. The succeeding volumes will be sent by the publisher for 
the following prices which are net:—Vol. II (1881) complete, $1.50; Vol. III (1882), out of print; Vol. IV 
(1883) complete, $1.50; Vol. V (1884) complete, $1.50; Vol. V (1884), Nos. 2-12, $1.00; Vol. VI (1885), $1.50; 
Vol. VII (1886), $1.00. 
