126 Mr John Eattray on the 



1. Oil bodies occur in isolated cells of the thallus and in cells of the 

 gemmae. They are emulsiform in character, and their colour is brown 

 in Marchantia 'polymorpha or brownish-red in Lunularia vulgaris. 



2. The reactions shown are generally similar to those found in 

 Eadula complanata, although dilute potash acts differently on the 

 oil bodies of Marchantia and on those of Lunularia ; in the former 

 the droplets fuse slowly, in the latter the oil bodies suddenly 

 disappear, unless the very dilute potash be slowly drawn under the 

 cover glass, an oU droplet inside a limiting membrane being then 

 formed. In this latter case the fat is in a finely divided state, 

 and easOy saponified. 



3. Tannic acid occurs in the oil bodies of Fegatella, Lunularia, 

 and Marchantia in small quantities ; it appears in oil bodies just 

 formed no less than in older oil bodies, and proteinaceous sub- 

 stances are also present in minute traces. As regards the tannic 

 acid, ferrous sulphate, with slight pressure, causes a deep "black- 

 blue " colour, which disappears after application of hydrochloric acid. 



Potassium bicliromate, again, does not alter the reddish-brown 

 colour of the oil bodies, but instead of being, as previously, soluble 

 in alcohol, they become insoluble, a similar reaction being found in 

 the case of the tannic acid drops in the joints of Mimosa pudica.* 



"With reference to the development of oil bodies, it is to be noted — 



1. That the oily droplets appear in the cell sap, though they may 

 lean against protoplasmic strings. 



2. That emulsiform or non-emukiform bodies are formed accord- 

 ing to the amount of fusion that is effected between these droplets ; 

 in the latter fusion is most complete. 



3. That the oil droplets appear either after cell divisions are 

 completed, and the chlorophyll bodies are formed, as in Nardia 

 sccdaris, or while the cells are dividing, and prior to the complete 

 formation of chlorophyll, as in MoMigohryum triholatvm. 



In the case of Radula complanata, a dim mass of droplets occupy 

 the entire lumen of young cells, a membrane forms around this ; as 

 the cell grows this dim oil body, not increasing in size, is surrounded 

 by a clear area ; but in basal cells of adult leaves, I have repeatedly 

 observed emulsiform oil bodies filling the cell lumen entirely, and 

 in such cells the chlorophyll bodies had the same shade of colour as 

 in other adjoining cells less oleiferous. These solitary od bodies 

 may have resulted from fusion of several smaller ones by mutual 

 pressure, although no traces of the faint membrane surrounding 

 each constituent body could be detected. Moreover, if two or more 

 oil bodies be present in a cell, they are to be found in the youngest 

 stages ; that is, oil bodies once formed do not divide. In Nardia 

 * Pfeffer, Physiolg. Untcrsuchungcn, 1873, p. \2ff. 



