AIZOACEAE 



198 a 



In many cases, however, the leaves are protected 



against the attacks of animals 

 by bundles of raphides (Fig. 88), 

 generally aggregated in special 

 tubes, and often also by more 

 or less numerous tannin-bearing 

 idioblasts, i.e. large cells filled 

 with a fluid rich in tannin (Fig. 88). 

 These correspond in their func- 

 tion to the balsam cells of the 

 aloe and the oil-receptacles of 

 the buchu and other Rutaceae. 

 Owing to their large size they 

 are easily noticed as colourless 

 spots within the green tissue. 

 Plow juicy and nutritious 



joaooooppopp e 



Fig. 88. M. noblle Haw. Long, 

 section through leaf (j/5 of water- 

 storing tissue only shown). e. ■ 1 



Epidermis, chi. Palisade-cells with some of the Mesembrianthema 



chlorophyll. f.b. Fibrovascular are j g snown b y tne analysis of 



bundle. w. Water-storing tissue. J J 



r. Raphides. id. Idioblasts (large the yOUng shoOtS of M. SpinOSUm \ 



cells), filled with solution of tannin. 



15/1. 







Digestible 





Mineral 







Water 



carbohydrates 



Proteids 



matter 



Fibre 



Fresh 



82-3 



10-5 



1-2 



3'3 



2-6°/ 



/ < 



Air dry 



12-3 



S3' 6 



5-8 



1 6-6 



127 



Some species of Mesembrianthemum possess toxic 

 properties. M. tortuosum, the "kauwgoed" of the natives, 

 produces a state of intoxication ; it contains a powerful 

 alkaloid, as was first shown by Mr Izaak Meiring 

 (Worcester). According to Prof. C. Hartwich (Zurich), 

 who recently named the alkaloid Mesembrin, its chemical 

 formula is C l6 H I9 N0 4 and its molecular weight 2 89" 14. 



When being dried the plant gives off a strong, almost 

 pungent odour, hence we think it quite possible that 

 this volatile body may contribute to the narcotic action of 

 the drug. 



* By Dr Ch. F. Juritz. 



