488 SCIENCE PROGRESS. 



to be rather for the purpose of effecting the ultimate, than 

 the initial, changes. The completed product can be some- 

 times detected in the protoplasm in the forms of small 

 droplets, often no larger than mere points or specks which 

 are stained brownish-black by osmic acid. The process 

 seems to correspond very closely to the action of the 

 leucoplastid in forming starch from the sugar supplied 

 to it. 



In certain plants peculiar corpuscles or plastids have been 

 found which have been thought to play a part in the de- 

 position of oil exactly similar to that of the leucoplastid in 

 the case of starch. These bodies have been called elaio- 

 plasts by their discoverer, Von Wakker (56). They have 

 not been seen in reservoirs where oil is present in great 

 quantity, but chiefly in leaves of various kinds. Von 

 Wakker found them in the epidermis of young leaves of 

 Vanilla ; Zimmermann (57) has described them as occurring 

 in the perianth of Ornithogalum and Funkia, and the leaves 

 of a species of Agave and in the root of Oncidium. They are 

 of various shapes, sometimes round or oval, sometimes very 

 irregular, generally lying near the nucleus in the cell. Each 

 consists of a stroma in the meshes of which the oil is slowly 

 formed. 



BIBLIOGRAPHY. 



(33) Gris. Ann. des Sci. Nat., ser. 5, Bot., vol. ii., 1864. 



(34) O'SULLIVAN. Transactions of the Chemical Society, 1886, 



49-70. 



(35) Brown and Morris. On the Germination of some of the 



Gramineae. Journal of the Chemical Society, June, 1890. 



(36) KUHNEMANN. Berichte d. dent. diem. Gesell., 8, 202 and 387. 



(37) Aime GiRARD. Compt. Rend. (1889), 108,602. 



(38) H. Lepley. Compt. Rend., 94 (1882), 1033. 



(39) BALLAND. Compt. Rend., 106 (1888), 1610. 



(40) GREEN. On the Germination of the Tuber of the Jerusalem 



Artichoke. Ann. of Botany, vol. i., 1888. 



(41) FREMY. Ann. Chiiu. et Phys., ser. 3, vol. xxiv., p. 1. Also 



Encyclopedic Chimique, Chimie des Vegetaux, p. 34. 



(42) MANGIN. Proprietes et Reactions des compose pectiques- 



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