PROTOPLASM 



PRUNE 



2813 



brane. or cell-wall, resulting in a high degree of rigidity 

 and strength. In some cases, as in "woody" tissues, the 

 cells become highly modified, the walls may be much 

 thickened, and the protoplasm may disappear, leaving 

 only the non-living cell-walls. 



Since the protoplasm is the seat of the greater part of 

 the chemical reactions and physical changes even in 

 the more complex living plants, with it must be asso- 

 ciated the absorption, digestion, and assimilation of 

 foods, respiration, and excretion, as well as growth, 

 reproduction, and heredity capacities. In the simplest 

 plants, such as many of the lower algae (pond-scums), 

 consisting of but a single cell, this cell must perform all 

 the functions of the organism; but in complex plants 

 there is a certain amount of differentiation of labor 

 or function of the various protoplasts, or cell units. 

 Thus the various tissues are more or less seats of differ- 

 ent physiological processes; for example, the nectar- 

 glands are "organs" of excretion, the green tissues are 

 the seats of organic food-making (see Photosynthesis). 



The protoplasm of the cell is itself differentiated into 

 various structures, important among which are (1) the 

 cytoplasm, or general protoplasm, within which are (2) 

 the nucleus, and (3) the plastids (in green plants). 



3196. Prunes. California prune on the left (Imperials Epineuse ; common 

 commercial on the right. ( X nearly H) 



Protoplasm is generally regarded as a viscid semi-fluid 

 material, and commonly it behaves as a liquid (an 

 emulsion colloid). When killed, protoplasm is "set," 

 that is, it becomes a jelly-like matrix, and it is a study 

 of such fixed material upon which have been based the 

 earlier views regarding structure. There is strong 

 evidence that much of what is called the finer structure 

 of protoplasm is a result of fixation, and that there is 

 actually little real ''structure" in the living material, 

 although certainly the gross appearance may change 

 more or less with the diverse activities of the cell. 

 Protoplasm cannot be expressed chemically; indeed, 

 the view which is today most widely accepted is that 

 it consists of numerous substances physically related, 

 rather than of complex molecules of a definite 

 "substance." B- M> DrcGAR. 



( PRUMNOPITYS: PoJocarpus. 



i 



PRUNE (from Prunus}, is used in this country to 

 designate a cured dried plum, and also the varieties 

 that are employed for the making of this product. In 

 literature, however, it may be used rather indefinitely 

 for many kinds of plums, particularly those that are 

 firm-fleshed; "dried prunes" is then used for the cured 

 product which in this country is known only as 

 "prunes." The product is now an important article of 

 horticulture and commerce in California and the Pacific 

 Northwest. It is also produced in southern and to some 

 extent in central Europe. 



Prunes in California. 



There are at least three important characters which 

 distinguish the prune interest of California from that of 

 any other state, viz.: the extent of the industry, the 

 method of curing, and the plum variety chiefly used. 



According to figures gathered by George P. Weldon, 



there were in California 91,470 acres of bearing prune 

 trees in 1915, and 24,774 acres of young trees. This 

 places the prune next to the peach, which is the leading 

 deciduous tree-fruit of California with a total acreage 

 of 144,888. The annual cured prune product of Cali- 

 fornia, during the decade 1905 to 1914, has ranged 

 from 57,000,000 pounds in 1908 to 205,000,000 pounds 

 in 1912, the average annual product being 122,050,000 

 pounds. The Pacific Coast States produce all the 

 prunes grown in the United States, and, according to 

 the United States Census of 1910, "California reported, 

 in 1909, 85.7 per cent of the total value of dried prunes 

 produced in the United States." The development of 

 this American product has not only reduced importa- 

 tion of European prunes so that they no longer receive 

 distinctive enumeration in the customs reports, but 

 about half the product is annually exported. 



There are several reasons why the prune product of 

 California is so overwhelmingly large and is still 

 increasing. Beyond the general suitability of natural 

 conditions for fruit-growing, there is, in the case of 

 plum varieties, the total absence of the curculio, and 

 "black-knot;" the practical freedom from rot-fungi 

 which attack ripening fruits, and a dry condition of 

 soil-surface and air during August 

 and September which favor 

 gathering fruits from the ground 

 and curing in the open air. 

 Curing in evaporators by artifi- 

 cial heat is practically unknown. 

 The process of handling prunes, 

 from the tree to the package, is 

 outlined by an experienced 

 handler, E. X. Richmond, of San 

 Jose, as follows: 



' 'Prunes should never be picked 

 from the tree. They should be 

 allowed thoroughly to ripen and 



fall to the ground. An orchard should be covered by 

 pickers every seven to ten days seven days preferably, 

 so as to prevent sunburn of the fruit lying on the 

 ground. The usual form of contract with pickers calls 

 for four pickings, no shaking of the trees until the third 

 picking, and then at grower's discretion. 



"The green fruit is hauled to the dipper-shed in 

 picking-boxes and there passed through a light solu- 

 tion of lye. A kettle or tank, holding 200 gallons of 

 water and containing a basket container, is used for 

 this purpose. In many instances the fruit is rinsed by 

 passing from this dip into a vat of clear water and then 

 dumped onto a combination pricking-board and grader, 

 operated by power, which grades the fruit into three 

 grades so that the drying in the field can be uniform. 

 The fruit is then placed on trays 8 by 3 feet and taken 

 to the drying-yard and dried in the sun. The purpose 

 of passing the fruit through the bye-solution and over 

 the pricking-board is that the skin may be slightly cut, 

 thereby hastening evaporation, preventing fermentation 

 and producing a fruit with a clear bright meat. From 

 the dipper-shed to the dry-yard, the fruit is hauled on a 

 one-horse truck especially constructed for this purpose. 

 "The operation of drying requires judgment. Fruit 

 should be allowed to lie in the sun on the trays until 

 about three-quarters dried, and then the trays are 

 stacked hi piles, one above the other, leaving air-vents 

 on either end. About twenty trays can be stacked in one 

 pile and the finishing process takes place in this stack. 

 Under normal weather conditions it takes from ten 

 days to two weeks to cure prunes. While the fruit is 

 on the trays in the dry-yard, it should receive at least 

 one turning by hand, shaking the traj^s or using brooms, 

 so that the fruit secures an equal drying on all sides. 

 It also materially lessens the time of drying and makes 

 a finer grade of fruit. The fruit must not be taken from 

 the trays until it is thoroughly cured. 



"At the packing-house the fruit is carefully separated 



