THE ALUMNI JOURNAL, 



269 



Plants without chlorophyll — and this 

 comprises parasites (living on other 

 plants) and saprophytes (living on de- 

 caying matters) — have the property of 

 assimilating such carbon compounds 

 (see under nitrogen) as cannot be as- 

 similated by green plants (Naegeli). 

 Yeasts, bacteria and moulds will absorb 

 sugar, mannite, the carbon group in leu- 

 cin, ammonium tartrate, and succinate, 

 the carbon group in asparagin, am- 

 monium acetate, ethyl alcohol, am- 

 monium quinate, benzoate and salicylate, 

 the carbon groups in propylamine and 

 methylamine and phenol ; they cannot 

 assimilate carbon in the form of cyanogen 

 compounds, urea, ammonium formate 

 and oxalate (Nageli). (3) Insectivorous 

 plants assimilate carbon compounds 

 (Darwin). 



II. Oxygen is taken up by the plant 

 from the air for purposes of respiration 

 and also combined with CO.,, H.,0 and 

 organic compounds for purposes of assi- 

 milation. All growth in fact is accom- 

 panied by oxidation of the assimilated 

 material (food ). Germinating seeds have 

 been found to take up oxygen and give 

 off CO,.. Experiments have shown that 

 all plants (when growing in a closed 

 space) have the power of absorbing all 

 of the oxygen present. The less chloro- 

 phyll a plant contains the greater seems 

 to be its avidity for oxygen ; but this 

 same plant exposed to intense light 

 exhales more oxygen. De Saussure 

 found that the essential organs of the 

 flower are those which absorb the largtst 

 proportion of oxygen and that the an- 

 drcecium does so more actively than the 

 gynaecium (Vines). It appears that the 

 absorption of oxygen is most active when 

 the flower is fully open. 



III. Hydrogen occurs in much smaller 

 amounts than either carbon or oxygen 

 and varies from 1.99 per cent, in ellagic 



acid to 12.82 per cent, in menthol. It 

 enters with carbon into the formation of 

 all the tissues and food of the plant. It 

 is absorbed by all plants in the form of 

 water and is also absorbed in the form of 

 ammonia, ammonium salts and also in 

 complex carbon compounds. Under 

 certain conditions, as when seeds are 

 germinated in a sealed tube, hydrogen is 

 evolved. This gas has also been evolved 

 when some parts of the olive, and indeed 

 when any part of a living plant, is insuf- 

 ficiently supplied with oxygen. Aquatic 

 plants under similar conditions give off 

 methane (CHJ. 



IV. Nitrogen enters into the composi- 

 tion of the proteids, the alkaloids, some 

 of the glucosides (cathartic acid) and 

 some of the neutral principles (aloin). It 

 varies from 1.17 per cent, in glycyrrhizin 

 to 15.65 per cent, in albumin and reaches 

 31. 1 1 per cent, in theobromine. Nitro- 

 gen is absorbed by the plant in the form 

 of ammonia and its salts, and as nitrates, 

 and plants containing chlorophyll may 

 take up such nitrogen-bearing com- 

 pounds as urea [CO(NHV). 2 ], glycycoll or 

 amido-acetic acid (C 2 H 5 NO,), asparagin or 

 amido-succinamide (C 4 H s N,0 3 ), leuein 

 or amido-caproic acid (C B Hi 3 N0 2 ) and 

 ty rosin or amido - hydrocumaric acid 

 (C.jHuNO.,). Some of these are decom- 

 position product of proteids while others 

 are from the urine of animals. Fungi 

 are capable of assimilating nitrogen in 

 the form of proteids, methyl-amine and 

 other amines. Naegeli concludes that 

 they assimilate nitrogen most readily 

 when it is supplied to them in the form 

 of NH,. Chlorophyll-producing plants 

 require ammonium salts for their best 

 development. Nitrates may be util- 

 ized by all except the lower plants. The 

 yeast, for instance, cannot utilize nitrates 

 (Pasteur). The following salts of am- 

 monium may be absorbed by the plant : 



