894 



SCIENCE 



[N. S. Vol. XLIV. No. 1147 



these later chapters are " XI., Biology of Bac- 

 teria, Yeast and Moulds; XII., Classification — 

 tlie ' Worms,' Mollusca and Arthropods ; XIII., 

 The Plant Kingdom; XIV., Some Biological 

 Adaptations; XV., Some Biological Factors in 

 Disease; XVI., Evolution; XVII., Variation- 

 heredity; XVIII., Animal Behavior and Its 

 Belation to Hind." From this outline it will 

 be seen that the author maps out a very exten- 

 sive program and it is not surprising that con- 

 sideration of many topics is very brief, and, 

 almost necessarily, inadequate many times. 

 An account of " The Plant Kingdom " in 23 

 pages can not be very satisfying. 



The style of the book is readable, but un- 

 fortunately is marred by many loose statements 

 and faulty definitions. The cell is stated to be 

 composed of the " nucleus " and " cytoplasm " 

 — a structure and a substance, instead of 

 nucleus and cytosome — structural subdivisions. 

 Many examples of such definitions appear 

 throughout the book. Physiology is defined as 

 " the work that an organism does or the work 

 of its parts " ; metamorphosis as " a name given 

 to the life-history of insects, frogs, etc." ; sym- 

 biosis as " the living together of dissimilar 

 plants or animals or a plant and an animal." 

 The illustrations are good and are properly 

 chosen to represent other forms than the ones 

 used in the laboratory. No laboratory outlines 

 are given and the brief and very general chap- 

 ter headings, called " Laboratory Studies," 

 would be of no service to a competent teacher 

 and are far too general to help an untrained 

 one. They could properly be omitted. 



C. E. McClung 



SPECIAL ARTICLES 



THE CAUSE OF THE DISAPPEARANCE OF 



CUMARIN, VANILLIN, PYRIDINE AND 



QUINOLINE IN THE SOIL 



PRELIMINARY NOTE 



Considerable attention has been devoted 

 recently to the fact that organic substances 

 which are toxic to higher plants in water cul- 

 ture lose their toxicity when added to the soil. 1 



i Davidson, J., Jour. Am. Soc. Agr., 7 : 145-158, 

 221-238 (1915). Upson, F. W., and Powell, A. E., 

 Jour. Ind. and Engin. Chem., 7: 420-422 (1915). 

 Praps, G. S., Texas Ag. Ex. Sta. Bui., 174 (1915). 



This depends, however, on the soil. 2 This loss 

 of toxicity would seem to be due to the fact 

 that the substances, as such, disappear in the 

 soil. 3 Funchess 4 has also found that many of 

 the organic nitrogenous compounds toxic to 

 plants in water culture are apparently nitrified 

 in the soil. This would point to their disap- 

 pearance as being due to biological causes. 

 Some observations made by the writer during 

 the past year on the cause of the disappearance 

 of four of these compounds may prove sug- 

 gestive to those who are investigating this 

 problem. 



Cumarin, vanillin, pyridine and quinoline 

 were added separately at a concentration of 

 1,000 parts per million to soil in pots. This 

 soil was similar to that used by Funchess, 5 in 

 which the organic toxins were found to lose 

 their toxicity or even become beneficial to 

 plant growth. The number of microorganisms 

 developing in the treated pots and in the check 

 pots was determined at intervals over a period 

 of about three months. In each case the num- 

 bers of microorganisms increased enormously 

 in the treated pots, after, in some cases, an 

 initial depression in numbers. The phenom- 

 enon appeared entirely analogous to that found 

 in partial sterilization. 



In order to determine whether micro- 

 organisms are concerned in the destruction of 

 the substances named above, the compounds 

 were added to sterile soil in two liter bottles. 

 Part of each set of bottles, treated with one of 

 the four substances mentioned above, was in- 

 oculated with an infusion from normal soil. 

 The bottles were incubated about two months 

 at room temperature. At the end of that time 

 sterile wheat grains were planted in the 

 bottles. The growth of the wheat plants 

 showed that in the inoculated soil the toxic 

 properties of the vanillin, cumarin, pyridine 

 and quinoline had largely disappeared, but 

 were still very evident in the bottles contain- 

 ing sterile soil. This seemed to indicate that 



Funchess, M. J., Alabama Ag. Ex. Sta. Tech. Bui., 

 1 (1916). 



2 Skinner, J. J., TJ. S. Dep't Agr. Bui. 164 

 (1915). 



3 Praps, loc. cit. 



* Unpublished data. 

 5 Loc. cit. 



