6 STUDY OF NUTS MICROSCOPIC IDENTIFICATION. 



METHODS OF EXAMINATION, 



Opaque structures, as preparations of integument, were cleared by 

 boiling on a slide in a strong solution of chloral hydrate and were 

 then mounted for examination in 50 per cent glycerin. 1 Sections 

 were treated in the same manner after leaching out the oil with ether 

 as they lay on a piece of filter paper. Preparations of aleurone 

 grains were made by scraping the tissue lightly and mounting the 

 scrapings in oil. Various oils were tried, as olive oil, xylol, etc., 

 cedar oil being finally chosen as giving most satisfactory results. 



In examining nut products the methods here outlined often have 

 to be modified according to the nature of the preparation. In the 

 case of almond paste it is usually possible to pick out from thin slices 

 fragments of the integument, which may be washed in water and 

 cleared for examination in chloral hydrate. It is necessary, how- 

 ever, to look over a rather large amount of the paste in order to find 

 a sufficient number of fragments for an accurate determination of 

 the source of the product. In examining a candy it is necessary 

 first to get rid of the sugar, which is easily done by dissolving in hot 

 water. The residue is then cleared for examination at once or after 

 treatment with alcohol and ether for the removal of oil. Products 

 containing large amounts of starch or flour, as cakes, pastry, etc., 

 should first be examined for large fragments of nuts by cutting 1 or 

 breaking into small pieces. The residue is then crumbled finely and 

 the official crude fiber method, as given in Bureau of Chemistry 

 Bulletin 107, Revised, page 56, is applied to get rid of the starchy 

 material and bring the residue into a satisfactory condition for micro- 

 scopic examination. Since less accuracy is required in preparing the 

 fiber for this purpose than in quantitative chemical work, the method 

 may be somewhat simplified by boiling for a half hour in a 1 to 2 

 per cent solution of sulphuric acid, filtering, and boiling again for 

 a half hour in a sodium hydroxid solution of about the same strength 

 as the acid. After filtering, the crude fiber thus obtained is ready 

 for examination in water or glycerin without further clearing. 



ALMOND. 



(Amygdalus communis L.) 

 GENERAL CHARACTERISTICS. 



The bitter almond and the hard-shelled and soft or paper-shelled 

 varieties of the sweet almond all belong to one species and are hence 

 very similar in structure. There is a series of intermediate forms, 



1 A very satisfactory clearing and mounting agent for temporary slides is made by dis- 

 solving eight parts of chloral hydrate crystals in five parts of water and adding about 

 5 or 10 per cent of glycerin. The glycerin prevents to a great extent the formation of 

 crystals even when the solution is boiled nearly to dryness. Mounts made in this way 

 may be kept for some time, but for permanent preparations it is better to mount the 

 cleared material in glycerin and seal with cover-glass cement or dehydrate and mount in 

 Canada balsam. 



