Infrared absorption spectra of plant and animal tissue and of various other substances

Supplementing a previous report on plant pigment s (BS R esear ch Paper 617) the present paper d escribes new data on the infrared absorption spectra of plant and animal su bst ances (cellulose and proteilJs) as found in nature and, in some cases, in the form of pure m at erial prepared in t he laboratory.The dat a were obt ained by m eans of a mirror spectrometer, portable vacuum thermopile, a nd ironclad Thomson galvanometer, described in previous publications.Th, e r egion of t h e infrared spectrum extending to 15", was examined.Outst a nding among th~ plant substances examined are samples of pure rubber, and associat ed materials-styrene, indene, polystyrene, and polyindene.The cellulose mat erials examined included Cellophane (commercial prEiparation) , onion skin, translucent membrane of pith of pokeweed, the seed septum of inoonwort, and the seed wing of the cotton tree.The protejn m a t erials exami ned included dried specimens of chitin (the outer integument of i nsect s) , pit h of feathers, a ir bladder of fish, bat's wings, fil m of dried egg albumin, commercial gelatin, lining of egg shell, and wing of a d ragon fly.The miscella neous subst ances reported upon are polyvinyl acetate and pol yvinyl chloracetate resins, glyptal resin, shellac, and a group of substances of interest in connection with the Raman effect,