200 



THE AMElilCAN MONTHLY 



[Oct., 1880 



n 



Another glass sent to me was a 4-10 

 inch of 100 ° (with removable front, for 

 use on opaque objects) ; now, though I am 

 not of the opinion that a 4-10 is all one 

 needs in histology, I believe that a 4-10, 

 if a good one, is the most useful objective 

 in histology, for, with this 4-10 inch, I can, 

 by the use of low eye-pieces, get a low 

 enough power for coarse structures and 

 preliminary investigations, and it will give 

 a clear, perfectly-detined image, with a 1-8 

 inch solid eye-piece. By its aid I have 

 followed and demonstrated the nerve ter- 

 minations in the cornea (gold staining) 

 where Powell & Leland's 1-4 inch, lirst 

 class (class 1872) did not give satisfactory 

 results. 



Henry Froehling. 



NOTES. 



— In reference to the statement on page 

 175, concerning Mr. Tolles' stands at the 

 meeting of the A. A. A. S., Mr. Stodder 

 desires us to state that he "exhibited ten of 

 Mr. Tolles' stands of six different construc- 

 tions, and one binocular eye-piece, all 

 contributed by friends who owned them." 



— The boxes of the Postal Microscopical 

 Club, which were held by the officers dur- 

 ing the Summer, have been started again 

 on their circuits. The benefits to be 

 derived from the operations of the Club, 

 might be greatly increased, if more care 

 were exercised by the members, in select- 

 ing the slides for purposes of instruction. 



— Mr. D. S. Holman has recently de- 

 vised, what seems to be the most perfect 

 compressorium that has yet been invented. 

 It differs from all others in being so ar- 

 ranged that the large cover-glass is fixed, 

 while the under-glass is moved up to it by 

 means of a screw. The advantages of 

 such an arrangement are very obvious. 

 Mr. John A. Ryder, in the Journal of the 

 Franklin Institute, states that he has 

 studied the anatomy of the beautiful Cor- 

 retha plumicoris with the instrument, 

 with great satisfaction, and it has enabled 

 him to demonstrate the presence of the 

 " polar vesicle " in the earliest stages of 

 the development of the shad. 



A combination of the animalcule cage 

 and the siphon slide, also devised by Mr. 

 Holman, seems to be a very valuable con- 

 trivance. In a siphon slide, shad have 

 been hatched under the microscope. 



We believe that the Holman compres- 

 sorium is not now in the market, and it is 



said that its excessive cost (about $8 or 10) 

 will prevent it from coming into general 

 use. We hope some makers of micro- 

 scopical apparatus, will provide a cheap 

 and useful substitute, if it is possible. 



Exchanges. 



[Exchanges are inserted in this column without 

 charge. They will be strictly limited to mounted 

 objects, and material for mounting.] 



Well-mounted, typical Pathological and injected 

 Histological preparations, in exchange for other well- 

 mounted slides, Diatoms, Algse and Fungi preferred. 

 HENRY FROEHLING, 

 59 N. Charles Street, Baltimore, Md. 



Diatomaceae from Lake Michigan (Chicago water 



supply), mounted or raw material ; also diatoms from 



other localities, to exchange for well-mounted Diatom- 



acese or other objects of interest. B. W. THOMAS, 



1842 Indiana Ave., Chicago, Ills. 



Lime sand, composed almost exclusively of micro- 

 scopic Foraminifera, to exchange for microscopic 

 material. H. A. GREEN, ^co, N. J. 



I would like to have the address of some person 

 who has access to an abundance of Volvox globator. 

 W. W. BUTTERFIELD, Indianapolis, Ind. 



Polyzoa, Palates of Mollusca, Foraminifera, Sponge 

 and flolothurian-Spicules, Synapta-Anchors, Chirod- 

 ota-Wheels, Echinus-Spines, Minute Sea Shells, in ex- 

 change for Polyzoa, Foraminifera, Histological and 

 Pathological preparations, etc. Also, a quantity of 

 Sea Shells in exchange for Land and Fresh-Water 

 Shells. 



F. M. HAMLIN, M. D., Auburn, N. Y. 



J. J. B. Hat^ld, Arsenal Avenue, Indianapolis, 

 Indiana, will exchange Bleached Plant-Sections for 

 good Diatomaceous material. List furnished on ap- 

 plication. 



Pleurosigmas and other unmounted Diatoms, both 

 Fresh Water and Marine ; also Marine Algae, Ferns, 

 and a large quantity of miscellaneous microscopical 

 material in exchange for good mounted objects. 



M. A. BOOTH, Longmeadow, Mass. 



To exchange, well-mounted Slides of Hair for 

 mounted or unmounted specimens of hair from the 

 rarer animals ; lists exchanged. WM. HOSKINS, 



208 S. Halsted street, Chicago, 111. 



Nicely mounted Slides (opaque) of the Coal-tar 

 Derivatives, chemically prepared, crystalline in form, 

 showing their beautiful colors, in exchange for other 

 well-mounted material. Chemical name and formula 

 attached to each Slide. About a dozen varieties on 

 hand. F. L. BARDEEN, M.D., 



30^^ Meigs street, Rochester, N.Y. 



Slides mounted from injected Frog's Gall-bladder, 

 Liver, Kidney, Stomach, Intestine and other parts, 

 exchanged for other good and interesting prepa- 

 rations. C. BLASDALE, M. D., 



Jericho, Queens Co., N. Y. 



Well-mounted, selected and arranged Diatoms, for 

 good histological, pathological or anatomical prepara- 

 tion. State what you have, and terms of exchange. 

 W. W. RINER, Greene, Iowa. 



