110 THE AMERICAN MONTHLY [May, 



and manifest certain of the protoplasmic powers in so high a de- 

 gree as to nearly exclude the others, but retaining the two most 

 universal powers of protoplasm — metabolism and reproduction. 



EXPLANATION OF PLATE. 



(All figures were drawn with the Camera Lucida.) 



Fig. I. Surface view of tuber, showing the 

 law of position of the buds, x % natural size. 



Fig. 2. Vertical section of the stem through 

 a bud, showing the bud with iis terminal por- 

 tion at ^, and its leaves at a, with the thin 

 layer of bark and the pith in which, parallel 

 with the bark, lies the fibro-vascular layer. 



Fig. 3. Vertical section of stem magnified 



imeters, showing (i) the bark cells at c I absolutely empty. 



cells filled with starch are reached at si in the 

 same figure. 



Fig. 4. Surface view of the bark cells mag- 

 nified 133 diameters. 



Fig. 5. Flat view of cells immediately be- 

 low the bark from the level marked rf in fig. 3. 

 After treatment with weak acid these cells, 

 before irrigation of the acid, appeared to be 



in rows, the edges of which produce the par- 

 allel lines seen in the surface view (I'ig. 4); 

 (2) the living subdermal cells specialized as 

 starch producers. The uppermost are full of 

 protoplasm (at ^ in the figure); below them 

 are cells containing large vacuoles and in which 

 the starch grains are forming (cf. figs. 7, 8,9). 

 There are only a few rows of these before the 



Figs. 6, 7, 8. Greatly enlarged views of nu- 

 cleus and surrounding protoplasm from cells 

 at level of e in fig. 3, showing the starch 

 granules surrounded by the protoplasm in dif- 

 ferent stages of formation. 



Fig. 9. Section magnified 240 diameters, 

 showing the fibro-vascular bundle with its 

 spiral cell and the cylindrical cells on either 

 side. 



The Decolorization of Preparations Stained with Osmic 

 Acid. — The staining power of osmic acid is very great, especi- 

 ally over the fat cells, and even with a very dilute solution it is 

 very easy to overstain. Peroxide of hydrogen in dilute alcoholic 

 solution will, to a certain extent, remove the excess of staining 

 matter. The proportion of commercial hydrogen peroxide is i 

 part to 8 or lo parts of alcohol, and 3 to 5 parts of distilled water. 

 The bleaching Huitl should be prepared only as needed. — Pacifc 

 Record. 



Shimer's New Mounting Medium. — This is made of equal 

 parts of Farrant's solution, glycerine, and glycerine jelly, the 

 last being made of gelatine, 30 parts ; water, 70 parts ; glycerine, 

 100 parts; carbolic acid, 2 parts. Of this jelly, licjuified by the 

 aid of a water-bath, pour i fluid ounce into a 4-ounce glass-stop- 

 pered bottle ; add an equal volume of the Farrant's medium and 

 of glycerine. Agitate, thoroughly mix, and add a small lump 

 of camphor. A little warming is necessary to make it fluid for 

 use. — Pacific Record. 



Ink for "Writing on Glass or Porcelain. — The Rundschau 

 (Prag.) gives the following: Dissolve in the water-bath 10 parts 

 bleached shellac and 5 parts Venice turpentine in 15 parts of oil 

 turpentine. Incorporate in the solution 5 parts of lamp-black. 

 So-called diamond ink for writing on glass is a compound of 

 fluoric acid and barium ; the latter has no effect, it being simply a 

 white powder to give body to the acid. The ink can be used with 

 a rubber hand-stamp, and it should be allowed to remain fifteen 

 minutes, when the barium will brush ofl', leaving the design on 

 tlic glass. — Nat. Drug: 



