INJUBY BY DISINFECTANTS TO SEEDS AND BOOTS. 6 



1.83. Kepeated parallel tests of C. P. and commercial sulphuric acid 

 failed to develop any difference in their effect on the seed beds. A 

 part of the hydrochloric and nitric acids used was C. P. and part com- 

 mercial. The ammonia used was the strongest commercial ammonia 

 water obtainable from local druggists (ordinarily 26° Beaume). The 

 formaldehyde used was the so-called 40 per cent commercial solution. 

 Because of the need of distinguishing between pure formaldehyde and 

 this commercial solution the latter will be referred to as formalin. 

 The general use of the term " formalin" for the commercial solution 

 appears to have become approved by custom, 1 despite the fact that 

 this term formerly applied only to the product of an English firm. 

 The lime-sulphur used was a commercial solution with a specific 

 gravity of 1.31. The mercuric chlorid used was C. P. and the cupric 

 sulphate was the fully hydrated crystalline form. The copper acetate 

 was neutral, containing a single molecule of crystallization water. 

 The zinc chlorid was a technical grade, granular, guaranteed from 95 

 to 98 per cent pure. All lime used was air-slaked. 



The unit of measure used throughout is the fluid ounce (29.574 c. c.) 

 for the acids, formalin, ammonia, and lime-sulphur solution, and the 

 avoirdupois ounce (28.35 grams) for the other substances. Except 

 where otherwise stated, all of the disinfectants were applied in aqueous 

 solution. When lime was used the powder was spread dry on the 

 surface of the bed and was worked into the upper 2 or 3 inches with 

 a rake. Two or three pints of water per square foot of seed bed was 

 found a convenient vehicle for applying the disinfectants. Because 

 of the variable moisture content of the soil the degree of dilution of 

 the solution before application is not of the greatest significance. 

 The amount of the disinfectant used per square foot of soil surface 

 is given in all cases as the measure of the strength of the treatment. 



PLANTS UPON WHICH OBSERVATIONS WERE MADE. 



The seed beds on which disinfectants were used were sown with 

 different species of pine. Jack pine (Pinus divaricata) was the species 

 used in most of the work, while western yellow pine (P. poTiderosa), 

 Norway pine (P. resinosa), and Corsican pine (P. laricio) were also 

 used, the relative frequency being in the order named. 



Weeds of various types appeared in the seed beds in addition to 

 the pines, and data as to their tolerance of disinfectants were also 

 obtained. Cryptogams were represented by a large-stalked species of 

 Equisetum, the algae conspicuous in many nurseries being present to 

 but a slight extent. Monocotyledons were represented by various 

 grasses, Eragrostis cilianensis 2 being much the most common, while 

 EchinocMoa crus-galli, Panicum harlipulvinatum, 2 and ChaetocMoa 



iPerkin, W. H., and Kipping, F. S. Organic chemistry, new ed., p. 124. London, 1911. See also 

 Webster's New International Dictionary, 1913. 

 2 Determinations made by Mr. P. L. Ricker. 



