Soil and Water Reactions 281 



SOME SOIL AND WATER REACTIONS IN THE DUNES 

 REGION OF PORTER COUNTY. 



Marcus Ward Lyon, Jr., South Bend. 



During a two weeks' stay, October 21 to November 4, 1923, at the 

 dunes of Porter County, devoted mainly to collecting small mammals, 

 I made a number of hydrogen ion concentration determinations of the 

 soil and water in the regions opposite Tremont and Mineral Springs, 

 stations of the Chicago, Lake Shore and South Bend Railway. My 

 interest in making the determinations came through knowledge of the 

 value of proper hydrogen ion concentration in bacteriologic work and 

 its still greater importance in our own body fluids, such as blood where 

 the normal range is within the narrow limits, Ph 7.6 to Ph 7.8, 

 specific alkalinities of 3.98 to 6.31. (At Ph 7.5 to Ph 7.2, specific 

 alkalinities of 3.16 to 1.58, the pathologic condition of acidosis ensues 

 and if the lower figure is maintained for any length of time death re- 

 sults.) The existence of two botanically diff"erent wooded swamps or 

 swamp-like areas, one opposite each of the railway stations mentioned 

 suggested further interest in the question as a possible explanation of 

 their differences. 



The method of making the determinations was that devised by 

 WherryS and use was made of the simple apparatus placed on the 

 market as a "soil indicator set" by the La Motte Chemical Company 

 of Baltimore. I found it desirable to use more test-tubes than accom- 

 pany the set. The results of each determination were reached by observ- 

 ing the color changes of at least three indicators rather than by basing 

 them on the specific color changes of one. 



The chief aim was to determine whether there were any average 

 differences in the soil and water acidities of the two wooded swamps 

 referred to rather than to determine the acidity of the soil of specific 

 plants. The differences in acidity of these two swamps were so slight 

 and almost inconsequential that I determined the acidity of other places 

 in the dunes. 



Each of the two wooded swamps seems about equally wet and 

 shaded. The swamp opposite Tremont is slowly traversed by Dune 

 Creek. The conspicuous plants found in it and not found in the Mineral 

 Springs swamp, or at most but sparingly are: Platanus occidentalis, 

 Carjnnus caroliniana, Asimina trifolia, Trillium grandiflonim, Trillium 

 sessile, Arisaema triphylhim, Arisaema dracontium.. 



The tamarack swamp opposite Mineral Springs station has prac- 

 tically no drainage although the water in it seems to seep eastward 

 toward the west branch of Dune Creek. The conspicuous plants found 

 in it and apparently not found in the Tremont swamp or at most but 

 sparingly are Larix laricina, Thuja occidentalis, Betula papifrifera, 



1 Wherry, Edgar T., Determining soil acidity and alkalinity by indicators in the 

 field ; Journ. Wash. Acad. Sci., Vol. 10, pj). 217-223. 1920. 



, Soil acidity — its nature, measurement and relation to plant distribution ; Ann. 



Rept. Smithsonian Inst., 1920, pp. 247-268, 1922. 



"Proc. Ind. Acad. Sci.. vol. 33, 1923 (1921)," 



