Vol. XIII. No. 316. 



THE AGRICULTURAL NEWS. 



191 



may be held in a teaspoon serves to make the 'body' of 

 a large dish of jelly. The proposal to use this simple specific 

 is one which certiinly deserves attention, but whether its 

 powers of adhesion are better than those of the substances 

 in general use remains to be determined. An objection 

 which occurs to the mind is the general one that in wet 

 weather the jelly-like skin formed when the sttitf is sprayed 

 on the plant would swell and wash oft' As, of course, is 

 well known, this property of many seaweeds to form with 

 boiling water a gelatine-like jelly is utilized in many ways 

 in medicine, commerce and science. Thus the stalks of 

 Laminaria are used in surgery, and a Japanese seaweed 

 supplies the source of agar agar, the medium so much used 

 in caltivating bacteria in the laboratory. {(rardeners' 

 Chronicle, April 2-5, 19U.) 



SOIL INVESTIGATION. 



PLANT GROWTH AND PARTIAL 



STERILIZATION. 



The Experiment Station Record (Vol. XXX, No. 3) 

 publishes the following abstract of Russell and Peth- 

 erbridges' recent paper on the above subject which 

 appeared originally in the J'lurnal of Agricultural 

 Science: — 



For a number of years experiments have been in 

 progress in growing plants in partially sterilized soils, and 

 some of the observed facts are placed on record. The 

 partial sterilization was effected by the use of toluene and 

 by heating to -5.5 ' and 100°C. 



The germination of seeds planted in these soils was 

 sometimes hastened, at other times retarded. Retardation 

 was almost always produced in soils heated to 100° or 

 treated with toluene, while acceleration often followed the 

 planting of seeds in soils heated to 5f>\ The retarding 

 effect was generally more pronounced in moist than in dry 

 soils and in rich than in poor ones. 



In the seedling stages the plants produced on partially 

 sterilized soils were sometimes indistinguishable from those 

 on untreated soils. Seedling tomatoes grown on heated 

 soils in comparison with those grown on untreated ones had 

 smaller roots and smaller cotyledons of a darker green 

 colour, frequently showing some purple. The effect on the 

 seedlings was most pronounced during the dull days of 

 winter, and this has a practical application in the use of 

 partial sterilization for the growth of plants under glass. 

 Later marked differences were shown, the purple colour 

 disappeared, and the plants began to show remarkable 

 growth. 



Sometimes soils treated with toluene behaved like those 

 heated to 55°, but on rich soils early development was 

 retarded. Other volatile antiseptics were found to behave 

 like toluene. 



Comparing partially sterilized with untreated soils, the 

 authors found that there was generally a retardation in 

 germination, although sometimes partial acceleration occurred. 

 An acceleration in growth followed up to the time of the 

 appearance of the third or fourth leaves, but sometimes 

 a marked retardation was noticed, especially in rich soils 

 heated to 100°. Where this retardation occurred it was 

 accompanied by a very dark green leaf colour and either the 

 formation of a purple pigment or a tendency for the leaves 



to curl toward the under.iide. Later the purple colour 

 disappeared, the curling ceased, and rapid growth took place. 

 The subsequent growth was finally proportional to the 

 amount of food present. Plants grown on soils heated to 

 100° showed a remarkable development of fibrous roots, and 

 in comparison with those on untreated soils, had larger 

 leaves of a deeper green colour, stouter stems, usually shorter 

 internodes, Howered earlier and more abundantly, and con- 

 tained a higher percentage of nitrogen and sometimes of 

 phosphoric acid in their dry matter. Plants grown on soils 

 heated to 55° or treated v/Ith volatile antiseptics showed 

 fewer of these effects. 



Considering the chemical differences in the soils, it is 

 stated that partially sterilized soils are characterized by aa 

 accumulation of ammonia, while untreated soils contain prac- 

 tically no ammonia. Soils heated to 100° are characterized 

 by the presence of decomposition products, some of which 

 possess characteristic colours and odours. 



The authors pre.sent the data upon which their paper is 

 based and give an extended discussion of their observations. 



In connexion with the above, a note published in 

 the same journal, on P. L. Gainey's investigation of the 

 effect of toluol and carbon bisulphide on the micro- 

 flora of the soil is of interest: — 



(1) Small quantities of CS.^, toluol, and chloroform, 

 such as have been used practically and experimentally, when 

 applied to the soils studied exert a stimulative rather than 

 a diminishing effect upon the total number of bacteria present. 



(2) An application of such quantities of CS^, and toluol 

 does not have an appreciable effect upon the number of types 

 of protozoa present in such soils as have been studied. 



(3) A very marked increase in yield may be noted 

 following such an application when no evident change occurs 

 in total number of bacteria present. 



(4) In the light of the recent work of Koch, Egorov, 

 Goodsey, Fred and others, with results presented in this 

 paper, the theory advanced Iiy Russell and Hutchinson to 

 account for the increased yield following the application of 

 such chemicals appears not tenable for general application. 



It has frequently been asserted that the characteristics 

 of an animal may be changed during the development of the 

 fcetus. That which is known of such cases as have been 

 reported, gives no ground for making them a basis of eugenic 

 teaching. It is true that during development the character- 

 istics may be adversely affected by malnutrition or through 

 accidents that may happen to the mother, but the so-called 

 'maternal impressions' have no scientific foundation. Besides 

 this idea of prenatal influence, we have also a series of myths 

 more scientific in aspect, but equally unfounded, under the 

 name of telegony. The first mate of a female animal is 

 supposed under this theory to affect or infect all her future 

 progeny. This idea is probably without any scientific founda- 

 tion either in man or beast. It is based on a misinterpreta- 

 tion of the single experiment where a mare once mated to 

 a zebra bore after to a horse father, a colt with traces of 

 dark bars or stripes. But such bars occur amongst horses 

 not suspected of zebra parentage. The original horse as 

 a wild animal was probably marked by dark stripes. (Pro- 

 fessor David Starr .Jorda-i, in the Journal of Herediti/^ 

 January, 19H.) 



