Investigations on the Phenomena of " Clot " Formations. 4GT 



greater their inhibitory action on the formation of aggregates by the larger 

 molecules contained in the system.* 



It is proposed to deal with the subject of the cholate clot in a subsequent 

 publication, but a preliminary account of certain experiments is given in this 

 place, as the results obtained have given rise to suggestions as to the 

 mechanism of a phenomenon of far greater general interest, viz., the clotting 

 of milk by rennet. 



From the fact that an aggregation, commonly known as a " clot," can be- 

 inhibited by the presence of simple adsorbable substances in a system, the- 

 conception arose that in milk the substances necessary for the formation of 

 the clot already pre-exist, but owing to their adsorption of simpler molecules 

 from the system, they do not aggregate, but remain in a state of dispersion. 

 It was thought that a ferment, for which the disperse phase acts as a sub- 

 strate, could clear the surface of the colloidal particles of adsorbed substances, 

 and thus allow their aggregation to take place ; in other words, the ferment- 

 could act the part of a scavenger. 



If the view here advanced is correct, it should be possible to produce clot 

 formation from a milk protein by the action of calcium salt alone, in the 

 absence of rennet. Indications of such a possibility are afforded by the 

 experiments published more than 20 years ago by Einger.f 



A more or less similar conception underlies the experiments recently 

 published by Hedin and his pupils. The former has shown that ferments., 

 such as rennet, are adsorbed by charcoal, and in this adsorbed state do not 

 exert their full activity ; if to such a combination another readily adsorbable- 

 substance, such as saponin, is added, the ferment can be freed from its 

 combination with the charcoal and its activity can be partly or wholly 

 restored.! 



Whatever chemical process is involved in the actual clot formation in 

 milk, it is a fact, which is illustrated by various experiments in this paper,, 

 that when aggregation is prevented by adsorbable substances, the inhibitory 

 action of the latter appears to be antagonised by the addition of an appro- 

 priate enzyme. 



* For other examples of salt action, see Schryver, " Investigations dealing with the 

 State of Aggregation of Matter, Parts I-III," 'Koy. Soc. Proc.,' 1910, B, vol. 83 r 

 pp. 96-123. 



+ ' Journ. Physiol.,' 1890, vol. 2, p. 464. 



t Hedin, 'Zeitsch. physiol. Chem.,' 1912, vol. 82, p. 175 ; and Jahnson-Blohm, ibid.. 

 p. 178. 



2 M 2 



