1344 
INDIAN MEDICINAL PLANTS. 
of very numerous bundles of needle-shaped crystals, and we also found similar 
crystals in the leaves and stems. These crystals were seen under the 
microscope to be insoluble in cold acetic acid, but easily soluble in cold 
diluted nitric or hydrochloric acid." “ There appears to us to be no reason 
to doubt the fact, that the whole of the physiological symptoms caused by 
Arums aro due to these needle-shaped crystals of oxalato of lime, and that 
the symptoms are thus duo to purely mechanical causes. Bearing in mind 
the action of re-agents on calcic oxalate, the reason why mere boiling in 
water failed to deprive them of their activity is explained by the insolubility 
of oxalate of lime in water. Again, the action of dilute acetic acid, even at 
temperatures of 100’ C., in slightly lessening the activity of the tubers, is 
due to the very slight solubility of oxalato of lime in that acid And, lastly, 
the complete loss of all physiological action when the tubers were treated 
with dilute nitric or hydrochloric acid is evidently duo to the ready solubility 
of calcic oxalato in those mineral acids. And these assumptions, as we have 
already indicated, were fully demonstrated by tho microscopic examination of 
sections of tho tubers treated with the reagents we have mentioned. One 
point, however, remains to bo explained : we observed that, on drying, tho 
tubers lost practically the whole of their physiological activity. Clearly 
there could have been no loss of oxalate of lime on desiccation, and, as a 
matter of fact, we found as many crystals on microscopic examination of dried 
Arums as we had found in the fresh tubers. We explain this apparent anomaly 
in the following simple manner. In the fresh condition of the tubers, the. 
bundles of crystals of oxalate of lime aro cone-shaped, more or less, the sharp 
points covering a wide area, and forming tho base, but, in the drying of the 
tubers, the needles appear to arrange themselves more or less parallel to one 
another, and the sharp points thus cover a smaller area. And thus, instead 
of each crystal acting as a separate source of irritation and ponetrating the 
tissues, the bundles act as a whole." (Warden and Pedler). 
1318 Alocasia Indica, Schott., h.f.b.i., vi. 525 . 
Syn. : — Arum- indicum, Roxb. 625. 
Sons. M&naka. 
Fern.: — Manakanda (H.); Mankochu (B. and Ass.) ; Alfi 
(Mar.). 
Habitat : — Generally cultivated around the huts of the poor- 
er classes in Bengal. 
Tuberous tall coarse herb. Stems attaining 8ft. stout, 3-8in. 
diam., emitting bulbiferous suckers. Leaves 2-3 ft. large, ovate 
deeply and sagittately cordate repand, lobes rounded very 
shortly connate, sinus narrow, nerves about 8 pail, petiole stout, 
transversely clouded. Peduncles (always in pairs, Roxb.) shorter 
than the petioles. Spathe 8-12in., pale-yellow, green ; tube 
