28 



The Growth of Seedlings in Wind. 



By Leonard Hill, M.B., F.E.S. (Director of the Department of Applied 

 Physiology, National Institute for Medical Eesearch). 



(Received October 16, 1920.) 

 [Plates 2 and 3.] 



The stunting of plants, and their more twisted, bent, and harder woody 

 nature is seen in wind-swept places, for example, the exposed shores of the 

 Shetland Islands. In Patagonia, where no shrub grows more than a yard or 

 so high, there is sunshine by day and ceaseless wind — an ideal spot for open 

 air treatment. Gardeners use hedges and rush hurdles as wind screens, and 

 secure luxuriant growth in exposed gardens by providing such shelter. The 

 kata-thermometer* gives a measure of the cooling and evaporative power of 

 the wind on its dry or moist surface at body temperature, and the powerful 

 effects of an open-air life with exposure to wind on the human body have 

 been studied. It seemed of interest, then, experimentally to study the 

 effect of wind on the germination and growth of seedlings. Mustard and 

 cress seeds were grown on lamp-wicks, which were kept moist by their ends 

 dipping in basins of water. 



The control seeds, in the relatively still atmosphere, were grown within 

 a glass jar on a damp lamp-wick. The jar was placed horizontally, with 

 one end of the lamp-wick dipping in a saucer of water. The seeds exposed 

 to wind were grown in a glass jar, the bottom of which had been removed, 

 and the neck inserted in the opening of the electrically driven fan, so that 

 air was sucked, or blown, through the jar at the rate of approximately 

 6 metres a second. The lamp-wick in this case also dipped into a basin of 

 water placed outside the jar. The blower-fan used was one made by Keith 

 Blackman, and was of the type used for ventilating war-ships. It ran day 

 and night with smoothness, and never failed during the whole course of the 

 experiments, which lasted many weeks. 



Some of the seeds exposed to wind did not sprout, some just sprouted, and 

 a few just showed two green leaves on the end of a very short sprout, which 

 was bent and horizontal ; the contrast with the control being very striking. 

 While the lamp-wick exposed to wind was quite moist, it appeared as if the 

 upper surface of the seeds exposed to wind might not be wet enough for 

 growth. 



* Leonard Hill, ' The Science of Ventilation and Open-Air Treatment.' Spec. Rep. 

 Series. Nos. 32 and 52. Med. Research Council. 



