232 M. Marc Micheli on some Recent 



relies to affirm positively the existence of this phenomenon. 

 According to him, the production of gaseous ammonia is a ge- 

 neral fact in the family of the Agarics ; the quantity of gas 

 exhaled is in proportion to the vital activity of the plant, but 

 has nothing to do with its weight. It is equally without any 

 relation to the production of carbonic acid as a result of 

 respiration. 



But quite recently MM. Wolff and Zimmermann* have ob- 

 jected to these conclusions. In all their experiments they were 

 only once able to recognize some traces of ammonia, and the 

 Agaric was not under conditions so normal as the others. 

 These two authors, therefore, believe that in the Agarics, as in 

 other plants, ammonia is a product of the decomposition of 

 the tissues, but a product which begins to make its appear- 

 ance immediately the vital functions of the organism are 

 slackened, 



Inuline, a substance of the starch-group, which is met with 

 in a considerable number of plants, has been made by M. 

 Prantl f the subject of a memoir crowned by the University of 

 Munich. 



The results obtained by the author of this memoir are in all 

 essential features in accordance with what MM. Nageli and 

 Sachs have said of inuline. M. Prantl describes this substance 

 as a hydrate of carbon, which differs from starch, cellulose, and 

 lichenine in never taking on an organic form. Its fixity suffi- 

 ciently differentiates it from dextrine. It seems to approach 

 most nearly to cane-sugar. 



Inuline is constantly found in plants in the form of a solu- 

 tion of 1 part of inuline to 7 of water. As in artificial solu- 

 tions O'Ol gramme of inuline saturates 100 cub. centims. of 

 water, we may suppose that when dissolving in the plant it 

 undergoes transformation. It never apj)ears excejit in subter- 

 ranean organs. 



This substance is pretty frequently produced in plants 

 of different families, but especially in the Compositee. The 

 dahlia and certain Helianthi contain considerable quantities 

 of it. 



From a physiological point of view, inuline plays exactly 

 the part of one of those nutritive principles which are put in 

 reserve, such as starch, sugar, oils, &c. As we have just said, 

 it exists exclusively in subterranean organs, tubers or rhi- 

 zomes. At the moment of growth it is transformed into cane- 

 sugar towards the collar of the root, then mounts into the 



* Bot. Zeitung, 1871, Nos. 18 and 19. 



1 Das Inulin, Munich, 1870 ; and Bot. Zeitung, 1870, No. 39. 



