137 



Besides histology, we will have to take etiolo^ es- 

 S^Si'^^^y/?*? consideration in the detailed description of the 

 different heteroplastic tissiieB and in the subdivision of our 

 material. In uhas we shall be able, repeatedly to make the 

 same groups a-s in the treatment horaooplastic tissues. 



,,, Aotivltyjheteroplasias of course ^7111 not be described. 

 All hyperplasias have boon disposed of above v/hich are pro- 

 duced by a greater amount of action and indicate a relation to 

 heteroplasic,s through their slight histological variation 

 from normally constructed tissues; 



^ Q2|g£3:j}f }o^^ -,^e |Q£$I2i2£|^£, produced after local firrestment 

 of growth, will need at least a short chapter. 



y-p^s-hoteroplasl r s (In the uldont sense of the word) 1. 

 ®Aj those heteroplastic tlssuRs thich are produced by wound- 

 (161) stimuli, are, very diverse ahd demand thorough discussion. We 



will have to describe in order the undifferentiated, homogene- 

 ous wound tiSBue or the callue (s. str,), the wound tissue re- 

 sembling wood, the woun d -wood, and that resembling cork.- 

 wound-cork . 



A new group must be taken ipto consideration here, for 

 which no analogy exists among horaooplasies, that is the eall- 

 heteroplusias produced by foroigh organisms, the mult IpliHITy 

 Of which exceeds that of all other tissues disclosed by the 

 sttidy of pathological plant anatomy. 



There are various other heteroplasias - and doubtless fu- 

 ture investigation will disclose still further forms - which 

 may not be Included in any one of the above named groups, based 

 upon etiological considerations, Sinco we have learned nothing 

 afi yet of the causes of their production, I have set aside no 

 separate chapter for them, but hJxve discussed them in connec- 

 tion with those of the above named tiaf;ues, with which they 

 best correspond histologically, 



If we nov; ask, wJiich role the kataplastic and prosoplas- 

 tic processes of differertiation play in the groups just dis* 

 tinguished, the follov/ing becomes evident. The corrolation- 

 heteroplasiaf so far as yet known have the histological charac- 

 ter of kataplasmas. The same is true ofcollus, wound -wood and 

 wound-cork. Among galls, we find kataplasmas and prosoplasmas 

 which we shall have to discuss separately. 



An equal considerrti on of the histology and etiology re- 

 sults in the following subdiwision of the material; 

 1, Gorrel ation~heteroplasmas ) 

 E. gilluses ) 

 3« Womi^-wo od ) Kataplasmas 



4. Wound-cork ) 



5, Galls ""* ( a. Kataplasmr:S 



( b.- Prosoplasmas 



1, Correlat ion-he teroplasmas 



Wo speak of correlation-he teroplasmas if the normal growth 

 of any plant Is arrested at its vegetative points by any factors 

 whatsiever, wherever under the ihfluence of the unused nutritive 

 materials, some part of the plant body is incited to abnormal 

 growth,- to the production of abnormal tissue. 



