106 Warden & Fedhr— On the Nafwe of the [No. 1, 



Another interesting definite integral may also be obtained from the 



formulae given above, viz.j we have from (11) 



„ ( 1 — e^) cos u 



e + cos6l = -^.j 



1 - e cos ti, 



whence from (13) 



^<9 /:; 5 (l-ecos«tr-^ , 



(e-t-cos^)^ (l-e2)^^cos^' 



Therefore, putting 



fi = cos a, 

 we have the relation 



r '1 = (cosec a)2"-l r a-cosacos^r-^ ^^^ ^^^^ 



Jo (cosa + cos^f Jo cos^^ 



IV. — On the Nature of the Toxic Principle of the Aroideae — By A. 

 Pedler, F. 0. S. (Lond. & Berl.), Professor of Chemistry, Presi- 

 dency College, Calcutta, and C. J. H. Warden, F. C. S. (Lond. & 

 Berl.), Professor of Chemistry, Medical College, Calcutta. 

 In the annual report on the Chemical Examiner's Department, 

 Bengal, for 1886, submitted to Government on the 18th February 1887, 

 we gave a brief resume of our investigations on Bish Kachoo, a variety 

 of Arum. We pointed out that the toxic effects of Kachoo were due to 

 purely mechanical causes, and that we were unable to isolate any 

 specific organic poisonous principle from the tubers. In the present com- 

 munication, we propose giving a detailed account of our investigations, 

 too-ether with an epitome of the most important points connected with 

 the genus Arum. 



Watt* describes the Arums as a genus of herbaceous plants, with 

 tuberous corms often edible, belonging to the natural order of Aroideae. 

 The genus comprises some twenty species, inhabitants of Europe, the 

 Mediterranean region, and Tropical Asia, and extending from India to 

 Afghanistan. 



Botanically, the leaves are sagittate or hastate, base of petiole 

 sheathing. Peduncles most frequently solitary, short or long. Spathe- 

 tuhe convolute : blade when opened out ovate or ovate-lanceolate : spadix 

 sessile shorter than the spathe, appendix naked, frequently stalked 

 and cylindrical, rarely clavate. Inflorescence monoecious, perianth none. 

 Female flowers below forming a cylindrical mass, separated from the 



Dictionary of the Economic Products of India, 



