rnbbei' does nol separate itself as a coliereiii coagiilum, liui in ihf 

 form of white tlocks. Tlie separation goes niiicli quicker than witli 

 higliei' concentrations and with the liqnids with 1 and 2i7o latex, 

 reminds one of a titration of warm nitrate of silver with hydro- 

 chloric acid. 



At those low concentrations tlie range of coagulation is so narrow, 

 that, in an acidified but still unchanged liquid, one can see, with 

 a single drop of diluted acid, the wiiite tlocks separating themselves, 

 and that one sees the original niilk_v liquid remain unchanged on 

 addition of a few drops more. With mixtures with S'/,, latex one 

 may get at first, with a small quantity of acid, a flocky separation, 

 cohering fairly ijuickly as a coaguliim; on addition of a little more 

 acid a veiT soft coagulum may be formed at once. Mixtuies with 

 2^" „ and 1' „ latex cause flocky separations, which may remain 

 unchanged for a long time, and with which the coherence as a 

 coagulum is the more diflficult, according as the mixture contains 

 less latex. 



At higher concentrations, just above 57,, sometimes the liquid 

 .separates itself in a remarkable quick way into a coagulum and a 

 clear serum, but the instantaneous coagulation is not found there 

 any more. At still higher concentrations the se|)aration of the coa- 

 gulum goes slower. 



The lower range of coagidation, described here, is limited by a 

 transition to s|)ontaneou8 coagulation, as discussed abo\e; at the 

 upper part we find a narrow lange of transition, where the mixture 

 after two hours is like pap or curdling (after 24 hours mostly 

 coagulated). Only towards the higher latex-concentrations this strip 

 gradually becomes a little broader, and at about 65% latex bends 

 itself in an upper direction, limiting the top of the liquid range, 

 and convei'ging into the broad strip, which separates llie liquid 

 range fr'orn the uppei' range of coagrrlalion. Thus the liquid range 

 is perfectly limited, both at the upper- and at the lower' side, at 

 least till the lowest coircerrtratiun, which was examined (17a latex, 

 so Ü.3"/, rubber' in the mixture). Whether, at still smaller concen- 

 ti'ations, tlie lower strip of coagulation is continued, or if both the 

 liquid ranges meet thei'e, has not beerr examined yet. The limits of 

 the various r-arrges ar-e found at the following norriialities of the 

 added acid in the final mixtur'e: (See Table following page). 



These figures are illiistr-ated by fig. 2. 



We shall now give a shori description of the course of the pheno- 

 nrena at a few typical (•oncerrtr'ations. To the latex-water'-nrixture 

 10°/, hydrochloric acid '0.914 N) was added from a burette; the 



45* 



