3l6 ORGANISATION IN SPACE AND TIME 



of oleic acid being arranged in a regular order between two 

 unimolecular layers of protein 



The films have definite structures and permeabilities which 

 depend on their chemical composition and electric charge. 

 For example, if the boundary film of the coacervate is nega- 

 tively charged and the surrounding liquid contains calcium 

 ions, the film is strengthened (forming an internally complex 

 coacervate with the adsorption of calcium ions). Potassium, 

 on the other hand, weakens the film. Thus calcium and 

 potassium act as antagonists in the coacervate. The proto- 

 plasmic films dividing the nucleus from the cytoplasm and 

 the nucleolus from the karyoplasm are similar in nature. 

 Many authors claim to have found such films around the 

 chondriosomes, karyosomes, chromosomes and other organ- 

 elles and inclusions in cells. 



The drops of protein coacervates also have an internal 

 structure which distinguishes them fundamentally from 

 simple drops of liquid. This structure manifests itself chiefly 

 as a rather labile state of orientation of the particles of 

 the coacervate. As we have already mentioned, complex 

 coacervates in the aggregated state take the form of more 

 or less freely flowing liquids, but under some circumstances 

 orienting forces may develop within the coacervates so that 

 they cease to behave like ideal liquids. These forces cause 

 the particles of the coacervates to assume a definite orienta- 

 tion with regard to one another. This may, for example, lead 

 to the anisotropy of some coacervates,^* although, at first, 

 they remain of a liquid consistency and their capacity for 

 double-refraction is very labile. 



According to Bungenberg de Jong,^^ the colloidal particles 

 in complex coacervates are not, as a rule, oriented in a 

 definite way, because in such coacervates there is no cohesion 

 between the particles. But if, by some means, the positive 

 or negative charge on the micelles of the coacervate is 

 increased or their hydration is decreased, then the micelles 

 approach one another and become oriented in a definite 

 mutual relationship. The so-called * oriented coacervates ' 

 which are thus obtained show many signs of having a struc- 

 ture. For example, if the particles of which it is composed 

 are rod-shaped, the drops of the coacervate will be ellipsoidal. 



