125 



differ from the normal and often exceed them in complexity. 

 Therefore, in all heteroplastic tissue formations, we will he 

 obliged* to prove what the Ratxire of the difference is between 

 normal and abnormal tissue differentiation. If less diffeten- 

 tiated tissue is produced by abnormal cell-division we can, 

 without regard to the abundant increase in cell numbers speak 

 similarly of a degeneration in the tissue formation, as we did 

 above (p. 87) of a degeneration of the cell, which was combined 

 with great increase in volume. We will speak here too of 

 KataT)las y and term Kataplasm as the products of kataplastio pro- 

 oessesJ-. If, on the other hand, new kinds of differentiation 

 processes make themselves felt in the formation of abnormal 

 excrescences, which are not known In the life history of cor^ 

 responding normal tissues, we v/ill speak of prosoplasia and 

 prosoplasmas, Further differences between katapiasraas and 

 prosoplasmas will be discussed later. 



Kataplasmas will be exclusively involved in most of the 

 tissue forms, with which we shall be conoprned when discussing 

 heteroplastic tissue. It will be shown that prosoplastio tis- 

 (137) sue formations may only be fotind among galls, but not that, 



conversely, all galls belong by any means to prosoplasmas, ;)ust 

 as this vefy extensive and varied group of abnormal tissue for- 

 mations is proved to be a homogeneous group, only etiologioally 

 e^nd not histologically. 



As was done in the preceding chapters, we will here base 

 the division of our material upon etiological and histological 

 characteristics: 



Group 1, Homooplasia , The abnormal tissue is composed 

 of the same elements as the original one , 



Group E, Heteroplasia. The abnormal tissue is composed 

 of otHer elemeircVthan is the original one , Those 

 heteaeoplastic products come under consideration as 

 the most important, which are produced after injury 

 (callus-formations), and those, which are caused by 

 parasites (gall-formations). 



Before we pass to the detailed discussion of different hy- 

 perplastic tissues, v/e must emphasize the fact that division 

 not infrequently takes place in plant cells, v/hich v;e must term 

 abnormal although no hyperplastic tissues whatever are produced 

 by it. The variation from the noriaal may consist in the abnor- 

 mal dir ect ion of the newly formed cross-walls, or in the forma- 

 ticn""o? the'new cross-wall at a "w rong pla ce", so to speak, 

 while keeping to the direction, so that tBe normal size propor- 

 tions of the daughter cells are not produced. Of course, on5.y 

 those abnormal cell-divisions belong in hyperplasias, by which 

 the cell-number produced, is abnormally large for the tissue 

 or organ concerned. Since no opportunity will arise later fcr 

 returning to abnormal processes of the first kind of cell-^di- 

 vision, a few examples may be mentioned here. 



Cell-division in abnormal directions may be studied espe- 

 cially easily in those organisms or organs, in the normal cell- 

 division of which, one definite direction 4s constantly repeated. 

 Raciborski^ observe'STon Ba sidiobolus rana rum that , by increased 

 concentration of the nutrient solution, the direction of the 



•^ In regard to Beneke's treatise by which the term 

 Kataplasy was introduced, bompare above p. 66, note 1. 



^ Raciborski, Ueb. d. Einfl. auss. Beding. auf. d, Wachs- 

 tumsweise des Basidiobolus ranarum. Flora, 1896, Bd. LXXXII, 

 p. 113. 



