526 EXPEEIMENT STATION EECORI>. 



spent mushroom manure are reported and briefly discussed. The air-dried 

 pigeon manure weighed 40 lbs. per bushel and contained nitrogen 6.17 per cent, 

 potash 1.51 per cent, and phosphoric acid 1.7 per cent. 



Analyses of commercial fertilizers, M. A. Scovell and H. E. Curtis (Ken- 

 tucky Sta. Bui. l.'iG, pp. 301-.'iOD). — This bulletin reports the results of inspection 

 of 515 brands of commercial fertilizers registered for sale in Kentucky during 

 1909. 



[Inspection of commercial fertilizers] (Missouri /S7ffl. Bid. 85, Sup., folio). — 

 Determinations of potash in 30 samples of fertilizers omitted from the original 

 report (E. S. R., 23, p. 26) are here supplied. 



AGRICULTURAL BOTANY. 



An experimental study of the rest period in plants, W. L. Howard (Mis- 

 souri Sta. Research Bui. 1, pp. 5-105). — In studying the hardiness of the peach, 

 it was found that this characteristic was intimately associated with the rest 

 period. In order, therefore, to arrive at a better understanding of this aspect 

 of hardiness, a study of the nature and principles of the rest period of plants 

 in general was undertaken. 



In this paper an initial report is made on the treatment for forcing into 

 growth of about 500 species and varieties of dormant (winter-rest) woody 

 plants, including maples, chestnuts, alders, beeches, hickories, hackberries, 

 dogwoods, hawthorns, elms, oaks, lindens, and fruit trees. It was found that 

 external conditions determine both the time of occurrence and the degree of 

 intensity of the rest period. If unfavorable conditions, such as cold or drought, 

 occur at regular intervals, the plant readily adapts itself to these new demands, 

 and resting becomes a habit which may continue to be repeated automatically 

 for a longer or shorter period, and may become strongly fixed and apparently 

 transmissible. 



The results are given of a large number of experiments on shortening the 

 dormant period, in which the following methods were tested: (1) B^ffects of 

 warmth alone: (2) treatment with ether only; (3) freezing, etherizing, and the 

 use of dark chamber; (4) etherizing, drying, freezing, and dark chamber, 

 singly or in combination; and (5) miscellaneous and special tests, such 

 as the use of chloroform, desiccating with alcohol, with salt solutions, and 

 wath sulphuric acid, etc. A careful study of the results of these experiments 

 seems to indicate that while these various agencies may quicken the growth, 

 they probably exert no specific action. 



A bibliography is appended. 



Influence of ultraviolet lig'ht on the germination of seed, L. Raybaud 

 (Compt. Rend. Soc. Biol. [I'aris], 68 (I'.HO), No. 15. pp. 772-777/).— Previous 

 investigators (E. S. R., 22, p. 436) have shown that ultraviolet light exerts an 

 injurious influence on green plants, and the author reports a study of the effect 

 of this light on the germination of plants, particularly of cress. 



The ultraviolet radiations, which were found to destroy the growing plants, 

 favored germination, the young plants not being injured for some little time, 

 possibly because of the absorptive power of their thin tissues. The death of 

 the plant followed shortly after the formation of chlorophyll, and this was 

 most active as the ultraviolet rays approached the violet portion of the spec- 

 trum. The central axis of the plants exposed to the light of a mercury vapor 

 lamp showed an abnormal position, which it is believed was due to the forma- 

 tion of long rectangular cells in the injured part of the plants. 



Osmotic pressures in plants; and a thermo-electric method of determining' 

 freezing points, H. H, Dixon and W. R. G. Atkins (Sci. Proc. Roy. Dublin Soc, 

 n. ser., 12 (1910), No. 25, pp. 215-311, fig. 1, dgm. 1).—A study was made of the 



