THE MOVEMENTS OF ORGANISMS 295 



muscle by a wire, we obtain a current of rest whose strength and direc- 

 tion depends on the nature of the neutral salt. [The study of these cur- 

 rents of action in the heart muscle has been elaborated into the science 

 of electrocardiography. I know of no attempt to associate electro- 

 cardiographic curves with changes in the colloids of the heart muscle 

 in response to salts. Tr.] If the anions and cations are arranged 

 according to their action on this current of rest (see R. HOBER and 

 WALDENBERG *), we obtain series similar to the above. Since we 

 have previously seen that the salting out of protein, the swelling and 

 shrinking of gelatin and fibrin (which means the ionization) occur in 

 similar lyotropic series, R. Ho BEE concludes that the normal irrita- 

 bility of muscle is dependent upon a definite condition of solution or 

 swelling of its protoplasmic colloids; increased solution or precipitation 

 of the colloids leads to loss of irritability. J. LOEB and R. BEUTNER 

 are of the opinion that the current of inactive muscle due to salt 

 (as well as the currents rising in plants because of an injury to some 

 part) bears no direct relation to the condition of swelling of the 

 plasma colloids, 1 but is due to a lipoid membrane on the surface of 

 the muscle or its constituent elements. The variation in activity of 

 the salts chosen (NaCl, KC1, etc.) is due to their different threshold 

 of solubility in the lipoid membrane. 



R. HOBER correctly emphasized that for such questions of physio- 

 logical function we need consider only those influences which are 

 reversible. Substances causing a more or less irreversible change by 

 means of aromatic anions require no further consideration here. 



The dependence of the irritab lity of muscle upon, and its relation 

 to, the condition of the organ colloids are not unique. Examples of 

 other organ functions were studied by R. S. LILLIE * 2 (movement of 

 the cilia of the larvae of marine annelids) and by R. HOBER* S (the 

 movement of the ciliated epithelium of the frog) . 



The movements of cilia above mentioned cease upon the addition 

 of various salts; in fact, of the alkali salts, Li salts are the most 

 harmful. In hemolysis and in the diminution of the movement of 

 cilia, the anion series shows an order the reverse of that for the 

 diminution of muscle irritability, which means that the swelling of 

 blood corpuscles and muscle are affected in an opposite way. Such 

 well-known hemolytic agents as saponin, solanin, taurocholic acid, 

 glycocholic acid and sodium oleate diminish the irritability of muscle 

 in an irreversible manner; they evidently damage the lipoid plasma 

 pellicle (R. HOBER * u ). 



1 We must forego further discussion of the extremely interesting results of 

 J. LOEB and R. BEUTNER since they have no direct bearing on colloids. 



