486 SPOKADIC DISEASES. 



and castor oil seeds the outer integument is washed away, and 

 the principal part of the testa remains black and opaque, and at 

 the edges some indication of the structure can be seen. 



Subjected to the action of sodium hypochlorite, even for 

 several days, the castor and ctoton seeds retain their colour, 

 wliilst those of linseed, cotton, locust bean, &c. are readily 

 l)leached. Free chlorine gas has a more pdwerful action, and 

 will gradually bleach both croton and castor seeds, but it requires 

 more time, and even at the end of three or four days their 

 colour is not entirely removed. 



After passing through this bleaching process the castor oil 

 seed testa has a much smooth(3r and shiny exterior than the 

 croton seed, and this is an important point in their distinction, 

 as microscopically the structure of each is very similar, being 

 built up of closely packed bundles of fibres of the same thick- 

 ness ; but on the outermost edge of a transverse section of the 

 croton testa there is thickening of each bundle of fibres, absent 

 in a section of castor oil seed. 



Experimentally Mr. Leather has added the testa of castor oil 

 seed, weighing • 22o gramme to 1 lb. cotton cake, subjected it to 

 the bleaching process, and has recovered • 200 gramme ; and out 

 of • 074 gramme croton seed testa mixed with 1 lb. cotton cake 

 recovered by picking out • 060 gramme. In performing these 

 experiments it was found that a mouldy croton bean became 

 bleached after the lapse of a day. When microscopically 

 examined, this bean was found to have been penetrated through 

 and through with a fungus. It may be mentioned that the 

 hilum of cotton seed does not bleach so readily as the other 

 portions, but there is no difficulty in distinguishing it, for the 

 pieces are round, have nO sharp edges, and are marked by 

 alternating rings of grey and black on the surface. If the 

 material to be acted upon is roughly handled, the testa is 

 Ijroken into small fragments, and may thus be overlooked. 



Differences in the appeara^ice of the outer integuments of the 

 Castor and Croton Seed. — Castor Oil Seed before Ueaching. — The 

 seeds are oval, and bluntly rounded at one end, while at the 

 other they come to a point, where there is an aril, easily broken 

 off. The testa or outer covering is smooth and glazy, grey in 

 colour, with very characteristic longitudinal striations of dark- 

 browE, yellow-brown, or black. 



