ARKIV FÖR BOTANIK. BAND. 1. 141 



published paper' forming a preliminary communication from 

 a detailed work on the subject, did not let it be clearly seen 

 that the condemnation of the theory previously mentioned 

 with which he now considers himself to be ready after a 

 comprehensive histological examination of certain rust pustules, 

 originated in, and is explained by a serious misconception of 

 the theory as stated by me, a misconception which can be 

 inferred too from some previous remarks of Marshall Ward/^ 



Under such circumstances' I cannot delay giving a few 

 explanations in order to prevent the further spreading of the 

 misunderstanding. 



1 first beg tu draw attention to the fact that my theory 

 consists of two essential moments. In the first place I have 

 asserted, that when it is a question of explaining the origin of 

 soral flecks (spots or sori of uredospores) in general, we have 

 to take into account not only external infection from the 

 surroundings (Uredo- and Aecidium-pustules), but also a 

 hitherto unnoticed internal germ of disease in one form or 

 another, and 1 have based my assertion of the existence of 

 an internal germ of disease on such numerous observations 

 in the open-' and such numerous experiments in isolated glass 

 houses,'^ that I venture to regard this existence as proved, 

 at least until sufficiently comprehensive proofs to the con- 

 trary have been produced from some other quarter. 



In the next place, when attempting to explain the form 

 in which such an internal germ of disease could be thought 

 to exist, I have expressed the hypothesis - grounded on 

 anatomical examinations - that in the life of the fungus 

 there may be a period of development previous to the my- 

 celium-stage when the fungus exists in a latent symbiotic 

 life with the protoplasm of the host, and I have proposed the 

 name »Mycoplasm> for the double organism 1 had thus sup- 

 posed. 1 have, however, expressly emphasized that it was 

 not my intention that this very intricate question should 

 by any means be considered as exhaustively solved, but that 

 I merely wished to maintain the hypothesis of Mycoplasm 

 until a better solution should he proposed. I have given 



1 H. Marshalf, Ward, On the Histolot/y civ. 



■^ H. Marshaf,!, AVarj), On the Relations etc., p. 200. 



' J. Eriksson, Sur I'orgine etc., T. 14, p. IH— 110. 



* J. Eriksson, Sur Vorigine, etc., T. 15, p. 1—50 [Extr. p. 125— ITiJ. 



