Mat 7, 1915] 



SCIENCE 



689 



Starkekorner " written by Naegeli in 1874. 

 This does not mean that there are not many 

 interesting and important problems connected 

 with the study of the starch grain, but the 

 solution of these can bp accomplished only at 

 the hands of the experienced specialist engaged 

 in' research or under the direction of a master 

 mind. 



Henry Keaemer 

 Philadelphia College op Pharmacy, 

 March 27, 1915 



SPECIAL ARTICLES 



THE OSMOTIC PROPERTIES OF DIFFERENT KINDS 



OF MUSCLE 



In two recent articles^ I have pointed out 

 that the osmotic properties^ of the smooth and 

 striated muscle of the frog and of the clam's 

 adductor muscle were strikingly different. 

 Loeb suggests^ that the differences observed by 

 me might be due to the fact that " the smooth 

 muscle of the stomach . . . can not be ob- 

 tained in as natural a condition as . . . striped 

 muscle . . . ." Still more recently, in an 

 article published from Loeb's laboratory, v. 

 Korosy* has enlarged upon Loeb's suggestion 

 and has described some experiments purport- 

 ing to uphold it. 



The reasons for thinking that the differences 

 in the osmotic behavior of the three types of 

 muscle mentioned above can not be due to 

 any difference in the manner of their prepara- 

 tion seem to me very cogent ; they have already 

 been largely given in my articles dealing with 

 the subject. But it has not previously been 

 possible to give them completely or to bring 

 them together into one place, and, in view of 

 the suggestions of Loeb and v. Korosy, it 

 seems worth while to do this now. 



The first difficulty which one meets in com- 



1 Meigs, The Journal of Experimental Zoology, 

 Vol. 13, p. 497, 1913; TJie Journal of Biological 

 Chemistry, Yol. 17, p. 81, 1914. 



2 By ' ' osmotic properties ' ' I meaa those prop- 

 erties of the tissues which determine the character- 

 istic changes of weight undergone by them when 

 immersed in various solutions. 



3 Loeb, Science, N. S., Vol. 37, p. 430, 1913. 

 * V. Korosy, Zeitschrift fur 



Chemie, Vol. 93, pp. 171 et seq., 1914. 



paring the reactions of smooth and striated 

 muscle is that cutting across the fibers or re- 

 moving the " natural surface " does not have 

 the same effect on the two tissues. Striated 

 muscle goes almost immediately into rigor in 

 the neighborhood of a cut across its fibers. 

 This condition is accompanied by acid forma- 

 tion,^ by swelling, and by the loss of irritabil- 

 ity and of the characteristic osmotic properties 

 of the tissue; it spreads gradually from the 

 point of injury to other parts. Cutting across 

 the fibers of smooth muscle causes a contrac- 

 tion which is soon followed by relaxation; 

 there is no tendency toward acid formation, 

 swelling or loss of irritability either in the 

 neighborhood of the cut or in any other por- 

 tion of the tissue. These facts, which are 

 ignored by Loeb and v. Korosy, are very signif- 

 icant; they suggest at the outset, what is con- 

 firmed by all my subsequent work, that the 

 fibers of striated muscle are surrounded by 

 characteristic semi-permeable surfaces, injury 

 to which produces profound changes in the 

 tissue; and that no such surfaces exist in the 

 case of smooth muscle. They are incompatible 

 with the view that the osmotic properties of 

 the tissues are alike. Finally, they show that 

 my preparations of smooth muscle, in spite of 

 the fact that their fibers have been cut, are 

 more nearly comparable to uninjured than to 

 injured preparations of striated muscle. 



But one need not stop here. The rigor, etc., 

 produced in the neighborhood of a cut across 

 the fibers of striated muscle spreads only 

 gradually from the injured to the uninjured 

 regions; hence, if the injured area be propor- 

 tionally small, the preparation will react 

 osmotically for the first hour or so very nearly 

 like an uninjured muscle. If a frog's sartorius 

 be cut across its middle, either half of the 

 muscle will have about the same proportions 

 of " natural surface " and " unnatural sur- 

 face " as the preparations of frog's stomach 

 muscle used in my experiments. Such a cut 

 sartorius reacts for the first hour in all re- 

 spects very much like an uninjured sartorius. 

 The strikingly different osmotic reactions char- 

 acteristic of smooth muscle showed themselves 



5 Fletcher and Hopkins, The Journal of Physiol- 

 ogy, Vol. 35, pp. 261 et seq., 1907. 



