284 



Miss D. J. Lloyd. 



The secondary rise of the curve is already quite clear at a concentration 

 P H = 8. In dilute solutions a steady maximum is reached. In strong 

 solutions (as in strong acid solutions) there is a secondary fall, showing 

 slightly at O002 normal, and as a violent descent, continuing until the 

 muscle is entirely disintegrated, at - l normal. This secondary effect of 

 alkali on muscle substance makes the numbers given in figs. 1 and 2 for the 

 maximum swelling less reliable than those given for the acid solutions. 

 They are the values obtained in 24 hours, and in strong alkalies (0 - 07— 0*1 

 normal) the muscles undoubtedly lose still more in weight. 



In studying the alkali curves, it is noticeable that, with a little experience, 

 it is quite easy to tell what point on the curve the muscle has attained 

 merely by taking note of its appearance. The muscle, when freshly excised, 

 is fairly translucent and yellowish in colour. In the early swelling stages, 

 besides visibly increasing in volume, it turns milky opalescent. As swelling 

 increases, the milkiness gets less and less, and finally a muscle swollen to its 

 full extent is clear and glassy in appearance. A muscle that is losing 

 weight always has its fibres contracted, and often retains a yellow tinge. 

 The history of a muscle hung in alkaline solution can thus be followed by 

 the eye — at first it increases in volume and becomes milky white, then it 

 shortens suddenly and becomes yellow and opaque, finally a glassy appearance 

 begins to show at the edges, and the whole muscle again becomes swollen 

 and clear. 



These changes are in intimate relation with the state of the muscle as an 

 electrically charged colloidal system. Evidence has been accumulating for some 

 considerable time that, in the body, the tissue colloids are charged positively, 

 and give an acid reaction. For instance, Fletcher and Hopkins (5) find that 

 working muscles contain between 0*2 and - 3 per cent, of their total weight 

 of lactic acid, and even in resting muscles they found a persistent minimum 

 of - 02 per cent. Hardy (8) has shown that, under the influence of an 

 electric current, the colloids of the cell cytoplasm migrate towards the 

 cathode, and it seems a just conclusion, therefore, that they are positively 

 charged. Bollas-Lee, in his ' Microtomist's Vade Mecum ' (28), describing 

 the technique of staining intra vitam with neutral red, states that tadpoles 

 take up this stain freely, becoming dark red in colour. Now, neutral red is 

 an indicator that is red in solutions with P H < 7, yellow in solutions with 

 P H > 8, and therefore this observation alone is sufficient to show that the 

 tissues are either neutral or acid, but not alkaline. Finally, my own 

 results are most easily explained on the hypothesis that the muscle colloids 

 are an acid, or positively charged system. Consider the muscle in situ as a 

 system in equilibrium with an alkaline fluid, the lymph, containing salts. 



