38 



Journal of Applied Microscopy. 



Gleditschia seed may be sectioned 

 free-hand, and for this purpose the base 

 of the razor blade should be used. It is 

 advisable to just moisten the seed with 

 a little water before cutting- with a razor. 

 This will prevent the otherwise brittle 

 material from being displaced. The sec- 

 tions should be laid in alcohol and then 

 mounted in water, when the mucilagi- 

 nous endosperm comes out very nicely, or 

 they may be mounted directly in potas- 

 sium hydrate, which preserves the struc- 

 ture of the mucilage. The malpighian 

 cells and osteosclerids can alsio be made 

 out, but these layers as well as the nutri- 

 ent come out better when mounted in 

 chloral hydrate. 



In order to show the nature of cell- 

 walls in different parts of the seed, 

 chloriodide of zinc is added to a fresh 

 section. The secondary membrane of the 

 endosperm colors bluish or violet, pore 

 canals are very distinct, the protein mat- 

 ter of the cell cavity colors brown. The 



Fig. 3.— Cassia occidentalis, Lfl Cross Sec- 

 tion of Endosperm (Mounted in Water.) 



n.— Nucleus and nucleolus. 



g. w.. — Gelatinous walls. 



p. — Primary cell wall. 



q. — Aleurone grains. 



e. — Pore canals. 



r. — Cell wall with minute rifts. 



f.— Fat globules. 



X 330. (Original.) 



cell walls consist of true mucilage 

 and act as reserve matter. It is 

 significant that the embryo contains no 

 starch. The chloriodide of zinc reaction 

 further indicates that the cell-walls of 

 malpighian cells color rather tardily 

 with this reagent. If a section is cut 

 through the hilum and treated with 

 phlorglucin and hydrochloric acid, the 

 tracheid island colors red. 



It is also easy to differentiate the vas- 

 cular bundle in the nutrient layer. Fresh 

 sections may also be treated with haema- 

 toxylin and analine colors for purposes 

 of differentiation. Ferric chloride will 

 show the presence of tannin not only in 

 the nturient layer and osteosclerids but 



also in the malphighian cell. The cotyle- 

 dons of pea and bean are used in nearly 

 all laboratories to study nucleus, starch, 

 and protein grains. These are indeed 

 excellent laboratory illustrations. 



Fig. 4.— Tamarindus indica. Cross Section 

 of Seed. 



r. a.— Reserve cellulose, amyloid. 

 p. — Primary cell wall. 

 g. — Aleurone. 



X 220. (Original.) 



The endosperm of date palm is com- 

 monly employed in laboratories to 

 demonstrate reserve cellulose, but the 

 endosperm of honey locust and Ken- 

 tucky coffee bean are as valuable. An- 

 other type of cellulose amyloid occurs 

 in the cotyledon of Schotia latifolia and 

 Tamarindus indica. This colors blue 

 with iodine alone. The seeds of Legumi- 

 nosae present many interesting histologi- 

 cal structures. The testa can easily be 

 preserved without staining When 

 mounted in glycerine jelly, glycerine, or 

 balsam. Specim3ns mounted ten years 

 ago are in excellent condition. 



Fig. 5.— Cassia occidentalis. Cross Section 



of mucilaginous Reserve Cellulose 



(Mounted in Potash.) 



g. w.— Gelatinous cell wall, 

 p. — Primary cell wall. 



c. w.— Cell cavity with aleurone grains 

 and fat (f.) 



X 220. (Original.) 



The seeds of crucifiers may be mounted 

 in the same way except the sections 



