170 FBAXINUS ORNUS 



the tree." According to Houel, flake manna is obtained during the 

 height of the season, at which period the juice flows vigorously ; 

 and Stettner states that it is procured from the upper incisions, 

 the juice being there less fatty than that in the lower part, and 

 that consequently, it more easily dries in tubes and flat pieces. In 

 the lowermost incisions small leaves of the ash are inserted to 

 conduct the juice into a receptacle formed by a cup-shaped piece 

 of the stem of the prickly pear (Opuntia), or on to tiles ; this 

 manna is more gummy and sticky, and less crystalline, and is of 

 inferior quality. Some manna also of inferior quality is scraped 

 off the stem after the finer flaky pieces have been gathered. 

 After the manna has been removed from the tree, it is placed 

 upon shelves to dry, and then packed for the market. In 1872 

 about 3500 cwt. of manna was exported from Sicily. It is 

 commonly packed in deal boxes, having partitions, and frequently 

 lined with tin plate. 



General Characters, Varieties, and Composition. Several kinds 

 of manna have been described by pharmacologists, but only two 

 are now commonly distinguished .in this country ; these are 

 known as Flake Manna, and Small Manna or Tolfa Manna. 

 Flake manna is the finest kind, and is alone official. It occurs 

 in pieces which vary from 1 to 6 or even 8 inches in length, from 

 1 to 2 inches in width, and from J to 1 inch in thickness. 

 Their form is more or less stalactitic, owing to the slow exuda- 

 tion of the juice and the deposition of successive layers over 

 one another. The pieces are commonly flattened or somewhat 

 grooved on the side where they have adhered to the tree or 

 substance upon which they have concreted, and on this side they 

 are also generally soiled. They have a pale brownish-yellow colour 

 on their inner surface, but are nearly white on their outer parts. 

 Good Flake Manna is crisp, brittle, porous, and crystalline in 

 structure, and readily soluble in about six parts of water ; it has 

 a faint odour resembling honey, and a honey- like taste, combined 

 with a very slight acridity and bitterness. The smaller inferior 

 pieces of manna are termed Small Manna or Tolfa Manna. 



The principal constituent of manna is Mannite or Manna- sugar, 



