ASSIMILATION OF ELEMENTS. 47 



tained in a well-manured soil must extend subsequently to every 

 part of the vegetable ; and it is easily understood that a plant which 

 has languished in its earliest periods of existence can never acquire 

 a good constitution afterwards. 



It therefore becamr interesting to carry out experiments of the 

 nature of those already related, in connection with plants vigorously 

 organized, and which had been raised in the first instance in a fer- 

 tile soil. 



FOURTH EXPERIMENT. 



GROWTH OF CLOVER. 



In a field of clover sown in the spring of the preceding year, 

 several plants as like one another as possible were chosen. The 

 earth adhering to the roots was removed by careful washing under 

 a small stream of water ; the plants were then made dry between 

 leaves of blotting paper, and exposed for a few hours in the air. 

 Three of these plants preserved for analysis weighed when green 

 5.750 grammes, or 104.20 grs. troy. 



Three other plants, weighing 6.820 gram, or 105.28 grs. troy, 

 were set in sand recently calcined and moistened with distilled 

 water. The transplanting took place on the 28th of May, and the 

 plants were forthwith protected from dust. 



For some days they seemed to languish, but by and by they be- 

 came remarkably vigorous. In a month the clover had grown to 

 twice its original height, and the leaves were of the most beautiful 

 green : the plants had in all respects as fine an appearance as the 

 clover of the same age which had been left growing in the field. 

 The flowers showed themselves upon the 8th of July, and by the 

 15th the flowering was complete : an end was put to the experiment 

 on the 1st of August. 



RESULTS OF THE ANALYSIS. 

 BEFORE CULTURE. AFTER CULTURE. 



Carbon 43.42 53.00 



Hydrogen 5.40 6.51 



Azote 3.75 2.45 



Oxygen ..47.43 38.14 



100.00 100.00 



RESULTS. 



Tlie trefoil transplanted, weighed when dry and freed from ashes 13.64 



After sixty-tiiree days' culture on iiarren soil, it weighed 34.96 



Gained during culture 21.32 



Carbon. Hydrogen. Oxyg-en. Azote 



The plant contained : before culture 5.92 0.74 6.4G O.r>0 



afterculture 1?.52 2.23 13.32 0.SG4 



Difference.. + 12.60 +1.49 +6.86 +0.35 



Thus in two months' growth at the cost of the air and water, the 

 clover had, so to say, tripled its quantity of organic matter; and the 

 weight of azote contained in it was very nearly doubled. 



