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4 



proven that this is the case, that bacteria are the means by which 

 some of the inorganic material of plant food is rendered fit for 

 their use, and we have another important link in the chain which 

 binds together all living organisms. This would also go far to 

 substantiate the theory that the tubers of the Leguminosae arc 

 caused by bacteria extraneous to the plant itself. 



One side point in connection with the tubers of Leguminoss 

 may be of interest. In a number of the Berichtc of 1887 is a 

 long article on this subject by Tschirch, also a member of this 

 agricultural college in Berlin. In this article he speaks of the 

 notion of Brunchoist that these bacteria-like bodies originate di- 

 rectly from the protoplasm of the cell, and adds that this idea 

 was also maintained by Prof. Wigand, of Marburg, in a paper, 

 not at that time published, on " The origin of bacteria in the closed 

 plant tissues of the root tubers of PapilionaccEe." He also adds 

 that although Prof Wigand agreed with Brunchoist as to the ori- 

 gin of these bodies, he differed widely from all other scientists in 

 the construction he put upon this supposed fact. It so happened 

 that I was passing through Marburg at the time Prof Wigand was 

 engaged in this study, and, at his request, I remained over one 

 day to watch the development of these supposed bacteria in cer- 

 tam root tubers then being studied by him. The plant was 

 Adoxa Moschatellitia. Since that time his unfinished papers 

 have been published, in which he gives a full account of these 

 and other experiments on which he bases his theory of Anamor- 

 phism. He was always very careful to distinguish between this 

 theory and that of "spontaneous generation" of earUer times. 

 He claimed that the active protoplasm of the cell underwent 

 some change, by which it passed over into these little bodies 

 which he called bacteria. 



The weak points in his and all the succeeding experiments 

 made in this direction appear to be these : It is impossible to de- 

 termine with certainty, first, that these bodies really are bacteria ; 

 second, if they are, what is their exact manner of origin. As 

 long as these two points are not satisfactorily known, any theory 

 based upon their presence, of course, can have no positive scien- 

 tific value. 



