THE TUBERS OF ANTHOCEROS TUBEROSDS. 51 



The oil is present in considerable quantity, as can readily be seen on 

 crashing a tuber in water between a glass slide and a cover, when large 

 fluid oil-drops exude. These are at once stained brown, or black, by 

 osmic acid. The drops are readily soluble in chloroform, ether, benzene, 

 but dissolve only slowly in absolute alcohol. The oil is not vaporised 

 by heating for two hours to 120° — 140 & C, and it is not readily 

 saponified with potash, even on heating for several minutes. The oil- 

 drops are fluid at the ordinary temperature (12°C), as can be seen on 

 compression. 



The granules present in the cells are of different sizes (Fig. 2) ; a few 

 are large, but the greater number are of smaller size. The larger 

 granules have an average diameter of "006 mm., the diameter of the 

 smaller granules being about "002 mm. Both larger and smaller grains 

 contain one, two, or three brighter and more refringent portions, 

 which may be enclosed bodies or only specialised portions of the 

 substance of the grains. The grains are swollen and dissolved by a 

 weak solution of potash (2%), and in some grains there is an inner 

 portion which remains undissolved for a short time. The granules are 

 not starch, as they are stained yellow by iodine. They give other 

 reactions for proteids ; e.g., they turn bright yellow when treated with 

 nitric acid and ammonia (xanthoproteic reaction), and they stain 

 readily with picrocarmine hematoxylin, aniline blue, acid fuchsin, and 

 other protoplasmic stains. The tests mentioned above prove that the 

 grains consist of some proteid substance, and they appear to be 

 aleuroue grains. 



The food material stored up in the tubers of Anthoceros tuberoms 

 differs, therefore, from that in the tubers of Fossombronia (n. sp.), which 

 were found by Ruge to contain considerable quantities of starch. In 

 the Synopsis, the tubers of Anthoceros tuberosum are said to contain a 

 farinaceous mass ; but it is necessary to remember, in considering this 

 statement, that the nature of aleurone grains was only discovered in 

 1 855, that is eight years after the publication of the Synopsis. 



The small size of the granules in the tubers of Anthoceros tuberosus 

 does not preclude the possibility of their being aleuroue grains, as in 

 some plants aleurone grains attain a diameter of only "001 mm. The 

 occurrence of larger and smaller grains in the same cell is also known 

 in other cases (e.g. Vitis). The occurrence of oil and aleurone grains 

 together as reserve food materials is not at all uncommon, but they 



