THE SOURCES OF THE NITROGEN OF VEGETATION, ETC. 555 



shade of Experiment No. 12 (with plants in garden soil), the latter being replaced by 

 the damaged shade after the crack had been mended with strips of bladder cemented 

 with albumen and lime-water. All the circumstances of this accident were carefully 

 considered, and it was concluded that no appreciable error could arise from it. 



June 24. — Three plants, 3 to 5 inches high; three or four leaves each; lower ones 

 dried up, upper ones pale green ; plants slender, but improved since the addition of the 

 ammonia-solution. 



July 4. — Plants 6 to 7 inches high ; five leaves each ; the most delicate and slender of 

 the plants that have had ammonia-solution ; upper leaves darker green than those with- 

 out ammonia ; lower leaves yellow. Second pipette-ful of ammonia-solution added. 



[The same remarks apply here, as were made to No. 1 at this date, in reference to con- 

 densation of drops of water.] 



July 11. — Plants 7 to 9 inches high; six or seven leaves each; stem reddish; upper 

 leaves healthy and deep green. Third pipette-ful of ammonia-solution added. 



July 22. — Growing vigorously. Fourth pipette-ful of ammonia-solution added. 



July 29. — Four plants, 16 to 20 inches high. Since the last two additions of 

 ammonia- solution, two of the plants have sent out at the base two new shoots, 6 to 8 

 inches high ; one, two new shoots 2 to 4 inches high ; and the other, one shoot. All 

 these shoots are deep green and growing vigorously. A great tendency to develope new 

 foliage ; and though some of the stems were just beginning to swell, indicative of head- 

 ing, and one showed a beard, yet this growth was arrested, and the energies of the plant 

 directed to the new growths at the base. In all, seventeen nodes clear of the sheaths. 

 Fifth pipette-ful of the ammonia-solution added. 



Aiujust 10. — Since the last three additions of ammonia the old stems ceased to develope, 

 but some of the new ones are on the point of heading. 



August 24. — Eight plants from the three seeds. One seed has given one plant 24 

 inches high, with seven nodes clear, and nine leaves, of which the seven lower ones are 

 dried up ; the plant terminated by a well-formed head. Another seed has four stems, 

 1G to 20 inches high; one dried up just as it was heading; the three others green and 

 healthy, and two just commencing to head ; each stem four to six nodes, and six to ten 

 leaves. The third seed has three stems 12 to 24 inches high, each with three to five 

 nodes and five to ten leaves ; one stem dried up. 

 October 8. — Plants taken up : — 



Eight stems from three seeds, as under : — 



(a) Seed with one stem ; 18 to 20 inches high ; seven nodes. This was the first plant 

 that headed ; all ripe and dry ; six glumes, containing only rudimentary or undeveloped 

 seeds. 



(h) Seed with three stems. One 17 inches high ; head ripe, and rather decaying. 

 Another 25 inches high ; grown several inches, and formed head, since August 24 ; head 

 green, with five soft milky unripe grams. The third stem green at top, and upper 

 sheath swollen with the head. 



