60 



THE AMEEICAN MONTHLY. 



[March. 



by a cloudiness that gathers on them and 

 is indehble. A. L. W. 



To THE Editor : — Your correspondent 

 G. T. asks for an efficient mode of " clean- 

 ing off old balsam-mounted slides and 

 covers." In my experience 1 have found 

 the following method as effectual as any : 

 I submerge them in rectified spirits of tur- 

 pentine until the balsam is dissolved ; I 

 then again submerge them in liquor 

 potassa and finally rinse with soft water. 

 E. W. Owen. M. D. 

 Brooklyn, N. Y. 



To THE Editor : — To clean old balsam 

 mounts, let them stand in a saturated solu- 

 tion of common washing soda two or three 

 days ; the balsam will become brittle and 

 easily rub off. S. Wells. 

 o 



To THE Editor : — I notice your reply 

 to G. T. about cleaning glass, and your 

 suggestion is a good one, but not exactly 

 what I think he needs. If an old slide is 

 warmed and the cover pushed off, and 

 then alcohol applied, the old balsam will 

 be disintegrated and readily rubbed off, 

 so that the glass will look clean, and will 

 be clean enough for many purposes. To 

 make it chemically clean it should be 

 placed for twenty-four hours in alcohol 

 and muriatic acid equal parts, and then 

 transferred to the solution you suggest for 

 three or four hours, and then washed 

 under a tap and dried by standing on end. 

 The bichromate mixture is the same as 

 ordinarily used in a bottle battery : Two 

 oz. bichromate of potash dissolved in 

 twenty fluid oz. of water, and then three 

 oz; of sulphuric acid gradually added. 



A careful mounter will clean all slides 

 before using them, even when they look 

 clean, and he will especially see to the 

 good condition of the cover-glass. 



D. S. W. 



NOTICES OF BOOKS. 



Description of Iowa Uroniyees. By J. C. 

 Arthur. From Bulletin Minn. Acad. 

 Nat. Sci., Vol. XI. (Pamphlet, pp. 37.) 

 Norfnal Condition of Cellular Structure 

 and Peach Yellows. By D. P. Penhal- 

 low, B. S. Houghton Farm, Experiment 

 Department. Diseases of Plants, 1882. 

 New-York, E. S. Dodge, Steam Print- 

 ing House, 95 Chambers Street, 1883. 

 (Pamphlet, pp. 45, and four plates.) 

 This is a record of experiments con- 

 ducted to determine the cause of peach 



yellows. The first part treats of observa- 

 tions on the normal condition of vegetable 

 structure with reference to cell-contents. 

 Numerous sections of different plants, 

 taken at various seasons were compared, 

 and the results summarized. With some 

 exception it was found that the quantity 

 of reserve starch in the cells is least during 

 active growth, and greatest just after the 

 fall of the leaves, and most abundant 

 in the old and most lignified tissues. 

 Leaves contain starch during their great- 

 est activity, but as they ripen oil takes its 

 place. 



As regards the yellows of the peach the 

 author does not believe it is caused by 

 fungus, but that it is due to low vitality 

 caused by impoverished soil. The pres- 

 ence of fungi is merely incidental, the low 

 vital condition enabling them to gain 

 foothold in the tissues. The colored plates 

 are instructive. 



The Recent Advances of Sanitary Scicjice. 

 The Relations of Micro-Organisms to 

 Disease. Annual address delivered 

 before the American Academy of Med- 

 icine, at New-York, October loth, 1883, 

 by Henry O. Marcy, A. M., M. D., Pres- 

 ident of the Academy, Member of the 

 British Medical Association, Correspon- 

 ding Member of the Midico-Chirurgical 

 Society of Bologna, Italy, etc., Phila- 

 delphia, 1883. (Pamphlet, pp. 24.) 



Remarks on Hydrophobia. Read before the 

 Philadelphia County Medical Society, 

 May 23, 1883, by Charles W. Dulles, 

 M. D. Reprinted from the Philadel- 

 phia Medical Times. (Pamphlet, pp. 12.) 

 The author combats the idea that hydro- 

 phobia is a disease produced by a specific 

 form of virus. He has compiled the 

 opinions of numerous writers, and reveal- 

 ed a very confusing mass of testimony 

 therefrom, which seems to bear him out 

 in the belief that we might study the sub- 

 ject more advantageously if the whole 

 mass of literature relating to it were swept 

 away. 



Exchanges. 



[Exchanges are inserted in this column without charge. 

 They will be strictly limited to mounted objects, and 

 material for mounting.] 



Will exchange various mounts of crystals for other 

 slides, and material for mounting. 



JAMES E. WHITNEY, 



Rochester, N. Y. 



Wanted — Physiological and Pathological prepara- 

 tions in exchange for Gorgonias, Starches, Micro- 

 fungi, Vegetable Hairs, &c. 



W. R. MANDEVILLE, M. D., 



154 Canal St., New Orleans, La. 



