(Edema of the Toma'io. 117 



was so great that within five minutes the fresh plants had been injected 

 and water stood out in great drops at the ends of the veinlets on the 

 edges of the leaves. This same phenomenon was observed in all the 

 ■plants when freshly connected with the delivery tubes. 



The exudation of drops from the edges of leaves through arti- 

 ficial injection of the plants has been observed by other experi- 

 menters, the water being forced into the cut end of the stem by the 

 weight of a column of mercury.* Sachs also has produced the same 

 effects in })lants, by simply warming their roots, thus increasing root 

 pressure, f 



Some of the lower leaves had been cut from each of the last three 

 plants connected with the tubes and from the cut surfaces a steady 

 stream of water flowed slowly down the stem. 



December 12th at 12:15 p. m., three of the plants were turgid while 

 one was a little drooped. The epidermis of the stem and petioles of 

 this one presented numerous longitudinal slits which perhaps offered 

 opportunity for freer evaporation, and during mid-day when the air was 

 comparatively dry and Avarra it became limp, while toward evening 

 (4:30 p. M.) it became turgid. In one of the turgid plants several of 

 the leaves presented quite extensive areas where the intercellular 

 spaces were injected so that these portions of the leaf exhibited a 

 water-soaked appearance, and drops of water stood out upon the lower 

 surface of such areas. In all of the plants a small amount was expelled 

 from the axils of some of the leaves, collecting in drops which flowed 

 away at intervals. 



One of the delivery tubes broke during the night of December 12th, 

 and on the morning of the 13th the water pressure was turned off. The 

 tube was repaired at 9 a. m. The temperature was quite low in the 

 house during the night of the 12th, owing to an accident in the boiler 

 room. Probabl}^ for this reason, coupled with the fact that the plants 

 were partly covered, little transpiration took place and the plants were 

 quite turgid. On December 14th there were no points of interest to 

 note. 



During the night of December 14th one of the delivery tubes broke 

 again and at the time on the morning of the 15th the pressure being 

 off, the plants had drooped. It was not deemed necessary to carry the 



* Moll, J. W. Ueber Tropfenausscheidung bei Blattern. Bot. Zeit., 1880, p. 

 49. Moll, J. W. Untersuchungen i'lber Tropfenaus-scheidung und Injection bei 

 Blattern, verslagen en Mededeelingen d. k. Acad, van Wetenschappen, 2, R, 

 XV, Deal. Amsterdam, 1880. See Just's Bot. Jahrb., 1880. i, p. 239. See also 

 Bot. Zeitung, 1880, p. 49. 



t Sach's Physiology, p, 378. 



