i893. NOTES AND COMMENTS. 91 



demonstrates the presence of small, colourless corpuscles in the leaves 

 of plants which have had no iron salts in their food ; on supplying an 

 iron tincture the corpuscles grow and become green. There is also a 

 short account of the properties, reactions, and distribution of the 

 oil-plastid. Two papers refer to the growth of the cell-wall, and one, 

 by C. Correns, is concerned with the internal structure of the cell- 

 membrane of some Algae. The last-named author also supplies an 

 account of some points in the structure and life-history of a green 

 fresh-water alga, Apiocystis Braimiana, Naeg. The volume is well 

 illustrated with five coloured plates and 23 figures in the text. 



In the Journal of Botany for July, Mr. Rendle has a note on a 

 potato which is depicted bringing forth young potatoes from its 

 interior through clefts in the skin. The occurrence which, though 

 previously described, has never been satisfactorily explained, is now 

 said to be due to the production of shoots from the base of the bud 

 or "eyes" as a result of the continued removal of the normal shoots. 

 The tubers were stored in a cellar as usual, and the sprouts which 

 appeared in the spring were plucked. In the case described the 

 potato, perhaps an exceptionally vigorous one, devised a new means 

 for using the large quantity of soluble nutrition which was being pro- 

 duced to supply the growing shoots, and as it was not allowed to form 

 aerial shoots, developed from the base of the bud where the chemical 

 processes would be specially active, tubercle-bearing shoots penetra- 

 ting the substance of the mother tuber, and providing themselves 

 with roots and a corky protecting covering in the same way as if they 

 were pushing through the soil. 



The writer refers to a similar physiological occurrence in the 

 Mexican Agave. The Indians cut off the large spike-like terminal 

 inflorescence at an early stage and then collect the sugary liquid 

 which the plant continues to pour into the scooped-out top of the axis 

 till it is exhausted, withers, and dies down. In both cases the chemical 

 processes are suddenly rendered useless by removal of the organ for 

 which the soluble nutrition was required; in both these processes 

 continue, in the Agave for the gratification of the natives, whereas 

 in the potato in question a new means for its use is devised. Of 

 course, as the young tubers grow the mother shrivels proportionately, 

 having to nourish its progeny from its own tissues. 



We regret to observe that the editor of the Journal of Botany has 

 taken to heart, as a serious criticism, a playful, but complimentary 

 note on the abundance of cryptogamic papers in his pages, which 

 appeared in Natural Scienxe for June. It has, however, given him 

 the opportunity of boasting the proud traditions of the Journal in the 

 matter of fair play — a thing well-known to all botanists, but not made 

 more savoury by an editorial announcement. 



