LIQUID CRYSTAL AND CONDENSER THEORIES 177 



nature and extent of crystallisation. The X-ray figures, however, 

 do not agree with Garner's. The advantage of this theory — ■ 

 Garner's or Clark's is that relatively large forces are brought into 

 play by an amount of lactic acid which does not need to be 

 sufficient to cover the whole area (see Chaj), TX. and Figs. 24 

 and 26). 



These statements about the crystalline structure of elements in 

 nmscle are very similar to the modern view of the structure of 

 rubber. Examination of rubber at rest (neither stretched nor 

 pressed) by X-ray interference methods leads one to the con- 

 clusion that it is formed of colloidal aggregates of large size. These 

 aggregates consist of highly polymerised rubber swollen by 

 imbibition of rubber not so highly polymerised. In this state the 

 free path of the molecules is limited and they yield no clear inter- 

 ference figure. 



If now the rubber is put under stress from any cause (Chap. XVII.) 

 the liquid phase is expelled from the aggregates to the continuous 

 phase. Clear interference figures — crystal like — are produced. 

 When released, the substance tends to regain its state of unstressed 

 equilibrium and the crystal structure disappears. The incorpora- 

 tion of a straight-chain fatty acid in the rubber leads to a great 

 increase in tensile strength, increasing with the length of the 

 carbon chain up to 14 carbon atoms, and giving marked X-ray 

 interference figures when put under torsion, stretch or compression. 



(5) Condenser Theory. Hill (1925) brought forward a new 

 conception, viz., that the fibrils, of which there are somewhere 

 about 100 per fibre, are little negatively-charged cylinders of 

 protein, surrounded by a cloud of attendant electrons, the whole 

 constituting a tiny condenser. " Such a condenser would be in a 

 state of strain under the mutual repulsion of the elements of charge 

 occupying its plates. The sudden liberation of lactic acid in the 

 neighbourhood of the negatively-charged protein surface would 

 cause a discharge of the condenser by the formation of sodium 

 lactate and ionised protein. The mutual repulsion of the charges 

 would then be obliterated and the condenser would tend to shorten. 

 The force developed in such a condenser suddenly discharged can 

 be calculated, provided we know its dimensions and the density of 

 its charge." Hill calculates that a monomolecular film deposited 

 on the surface of the condenser could easilv account for the 

 liberation of a force of 5,000 dynes per cm. edge (cf. Fig. 14). 



The temperature co-efficient for a complete muscle cycle is 

 1-8, which means that the rate of the physico-chemical reactions 

 involved is almost doubled by an increase of 10° C. As we have 

 seen this rate is a compromise between the decrease in the 



U. 12 



