Thc precipitntion of Rtnrch from the nqueous solutions of tliu fractions obtnincd froni wlicnt sthrch ground in a bull mill hns been inrestignted, togetlicr with ccrtnin solutions of the C.W. Sol. atid H.11'. Sol. fracliotis* properties of tho dried prccipitnted stnrch, drying bcing by n~collol ctller rind in Tho I n rnost cnsps thc nddition of iilcoliol (fiiinl conccntrnof aoluliility shown by stnrch frnctions on drying him been ti011 70% V./V.) precipitated a slnnil quantity of starch, found to bo governed, infer d o , by tho mean moleculnr the grentcr proportion reinnining ns a turbid n d k y sol wci611ts of tho frnctions and to d W n d on tho method of in the olcoliol-wnter mixture, but 011 occnsion, noticeable prccipitntion took place without the addition of elcctro-drying cmploycd.
Starch solutions, from which gelntinised grnnulcs or lyte, thc renson for this not bcing understood nt their debris are nbsent, are known to be similnr in general present. The nlcoholic stnrcli sol could be kept uncolloidnl propertics to the other common I~ydrophilic changed for n consitlerrrblc time a t rooni tcnipcrnturc, '' Iiigh-inolec~~lnr " cnrboliydrntcs such as ngnr, pcctiu, but whcn a smiill quantity of 5% sodiuni cliloridc ctc.1 Tlic bchnviour of thc nqucous solutions of such solution wns ndded, ininiedinte prccipitntion took plncc. substnnccs on tlic addition of iilcohol (or sonic sin~ilnr Aqueorls solutions of the /?-ninylose frnctions of wheat dchytlrnting iigcnt such ns iicctonc) hna been \vorked out nnd potato sturchest liehnvcd sirnilnrly to thosc of tho in sonic dctiiil by Iirnyt,l wlio sliowctl tlint two stnbility H.W. Sol. nntl C.W. Sol. frnctions on the nddition of fnctors exist in such colloidnl solutions : ( a ) the electric nlcohol. On all occnsions, the last trnces of starch clitirgc (ncgritirc in tlic cnse of st:ircV) 011 the colloidnl sepnrntcd out very slo~rly lifter the mnin bulk lind been pnrticlcs nntl (I) the hydration of the pnrticles. Both tlic prccipitntcd, wntcr-clcnr super~~ntnnt solutions bcing clcctric clinrgc nntl tlic liydration effect have to lie over-obtnincd ody after kccpilig for 2-3 dnys nt room conic before the clissolvcd colloid cnn be prccipitntcd teinpcrnturc. Thcsc obserrutions nre largely in nccord from solution. Tl~csc fnctors nrc rcntlerctl of no effcct, with Kruyt's theory of the prccipittrtion of starch from in the case of ( a ) by thc nddition of s n d l qunntitics of its aqlleous solutions by n dehytlrnting solvent nnd nn electrolyte, i i n d in tho cnse of (6) by tlic iiddition of electrolyte,' and with the rcsultv of other investigators dcliytlritting ngcnts (such us ethyl or inethyl nlcohol, workiiig with stnrch frnctions prepnred in various ucctonc, ctc.) iii sufficient quiintities. The addition of w n y ~. ~~