386 PROFESSOR C. R. MARSHALL ON THE 



in twenty to twenty-five seconds after the application, and very soon the contractions 

 became frequent and irregular and often clonic in character. At times, and especially 

 after a considerable interval had elapsed, the whole muscle contracted. If the muscle 

 were not dried, contractions of one or more of the adjoining thigh muscles occurred 

 simultaneously with those of the sartorius. If a drop be applied to one of the seg- 

 ments of the rectus abdominis, contractions of a portion or of the whole segment 

 occur at first towards the drop. Later they assume the irregularity which characterises 

 their occurrence in other situations. The contractions were always limited to the 

 segment to which the solution was applied ; they did not extend to the segments of 

 the muscle of the same side or to those of the muscle of the opposite side. When 

 concentrations of 1 in 1000 in Ringer's solution were used, many muscles did not 

 react with a single application, and in some cases several applications had to be made 

 before contractions were obtained ; and in those which reacted a longer interval 

 occurred before the first contraction appeared. By employing these small concen- 

 trations it can readily be shown, as Langley found for nicotine, that different muscles 

 are differently affected quantitatively by tetra-ethyl-ammonium chloride. The order 

 of susceptibility of those tested, the most susceptible being placed first, has in my 

 experiments been : myo-hyoid and sternal portion of pectoral ; rectus abdominis ; 

 adductor longus, sartorius, ulnar ; tibialis posticus, semimembranosus ; gastrocnemius, 

 deltoid. Whether the differences are associated with variations in physiological 

 activity of the nerve-endings, or whether they are wholly or in part, as seems probable, 

 due to differences in rate of penetration into the different muscles, was not determined. 

 A few perfusion experiments were made, but they did not help to solve the problem. 

 When a minimal stimulus of 1 in 5000 in Ringer's solution was perfused at the rate 

 of 1 c.c. per minute through the vessels of a pithed frog, slight twitches appeared 

 first in the hand and digits and afterwards in the leg ; and stronger solutions affected 

 the arm muscles and abdominal muscles before those of the leg, but in one case the 

 leg muscles were affected before the trunk muscles. It is possible, however, that these 

 variations may have been due to differences in the rate of flow of the perfusion fluid 

 through the different parts. 



The application of a small drop of an isotonic solution to the proximal end of the 

 sartorius produced no contractions ; nor were contractions obtained after a dose of 

 curare or of tetra-methyl-ammonium chloride sufficient to paralyse the nerve-endings 

 had been given. The application of solutions of tetra-methyl-ammonium chloride to 

 exposed muscles usually produces, however, tremors and contractions similar to those 

 seen after tetra-ethyl-ammonium chloride, but the effect is transient, apparently owing 

 to the more powerful paralysing action of this substance. The application of a 

 solution of tetra-ethyl-ammonium chloride subsequently induced no effect. 



Influence of Calcium Ion on the Production of Tremors. — The fibrillary tremors 

 produced by guanidin were shown by Fuhner * to be prevented by the previous 



* Arch.f. exp. Path. u. Pharmak, lviii. p. 16 [1907]. 



