43 2 The Physiology of Plants BOOK in 



to seek a fuller explanation of the apparent differences in 

 nutrition. Max Schultze's view of the identity of nature 

 of the vegetable and animal protoplasm was demon- 

 strated to be well founded by the various researches to 

 which attention has been drawn in the preceding chapters, 

 and by others to be treated of later which will deal 

 with the problems of sensitiveness or irritability. We 

 consequently gained the idea of nutritive processes which 

 are fundamentally similar in the two cases, and were 

 led to see that the special property of the green plant 

 is to carry on the manufacture of the food material 

 of both animals and plants, a manufacture which precedes 

 the nutritive processes proper, and which is not shared in 

 by the animal organism, except in a few cases. 



The distinction between the two sets of processes, which 

 had not been clear in the current ideas of the nutrition of the 

 plant, was gradually made more evident by the researches of 

 the whole of the period under review, and as this distinction 

 became more and more apparent, considerable light was 

 thrown upon many observations made during the time, 

 which when first noticed received no adequate explanation 

 and were held to be abnormal. Attention has been called to 

 the researches of Boehm, Meyer, Schimper, and others, which 

 showed that plants are capable of absorbing sugar under 

 appropriate conditions, and that this can be taken up so freely 

 as to give rise to the deposition of reserve stores of starch. 

 Hampe as well as Knop and Wolff showed in 1865 that green 

 plants are capable of utilizing the nitrogenous compounds 

 glycocoll, asparagin, leucin, and tyrosin when supplied to 

 their roots. These somewhat complex substances are all 

 associated with the digestion of protein in the animal 

 body and subserve in some way its nutrition. The group 

 of Fungi stood out as differing in an apparently funda- 

 mental manner from the green plants, for no true Fungus 

 is capable of utilizing atmospheric carbon dioxide. Obser- 



