225 



2, Or it nay be a question of an abnomal form and struc- 

 ture of the cell organs - such as the abnormal form of the dor- 

 mant nuclei, the abnormal distribution of its chromatin, abnoi-- 

 mal figures in cell division, or of amitoses, pseudo-amitoses, 

 abnorrasEl cytoplasm structures and so forth, 



3, Or there may exist variations from the normal condi- 

 tions of size and number - hypertrophies of the nucleus, in- 

 crease of the cytoplasm, definite kinds of cytoplasm, of vacu- 

 oles, nuclei, nucleoli, contraction of the various organs, and 

 so forth, 



Besides this, those various processes of degeneration come 

 under consideration, v'hioh might be Separated only Vith diffi- 

 culty fi-Om many of the phenomena here described. 



fg64) If I -have given hero no detailed treatment of cytological 

 questiohs, it -.vas because otar present kno-jledge of the normal 

 oytolOgioal processes seems to me still too little understood 

 to viartant an all inclusive discussion of the abnormal condi- 

 tions. I hr-ve therefore limited myself to calling attention, 

 here and there in the text, to changes in the nucleus, the 

 figures in the cell divisions and so forth, if the abnormal cy- 

 tological conditions seemed suited for completing the character- 

 ization of any abnormal tissue forms, The short blbliogtaphical- 

 summary given here v/ill perhaps suffice, for the present, for 

 further orientation, 



The phenomena of defeneration and necrosis can be consid- 

 ered as physiologically ;7ell-^characterized sub-divisions of 

 those nazodd above. 



It is according to r;hether v;e take into consideration the 

 parts of cells v;hich disappear during degenerative processes, or 

 those newly produced products of decomposition, that v;e ■.ill 'be 

 able to distinguish various groups of degenerative phenomena, 

 v.'hlch I have mentioned only by -..ay of suggestion In the preced- 

 ing chapters and then only if they helped to characterize the 

 abnormal tissues \:hich interested us. 



Of primary interest is the degenerative disappearance of 

 the cytoplasm, of the nucleus and of the chroraatophores In 

 starving cells (phenomena of inanition), in the parts of tissues 

 sucked dry b;r parasites, or in those cells \'hich are incited to 

 abnormal (kataplastic) grovrth by some stimulus (hyperhydric 

 tissue p, 80, "callus hypertrophies p. 93 and many others). The 

 protoplast becomes inpoverished, the nucleus disappears, the 

 chroraatophores become paler and smaller apparently changing 

 back into leucoplasts. Many of the cases described above prove 

 that all the living parts of the cell degenerate equally quick- 

 ly and in the same way; that under conditions, v.-hich, for example 

 do not endanger the continued existence of the nucleus, the very 

 sensitive chlorophyll grains can disintegrate and the like; of 

 that the cytoplasm often can outlast the nucleus and the walls 

 of the vacuoles in the former often prove themselves to be the 

 most resistant parts. 



All parts of the plant cell can be changed degeneratively. 

 We can distinguish, according to the products formed, a 



slimy and gummy degeneration to vrhich whole cells, includ- 

 ing their ceHtilose covering, v)R7 often fall victim (diseases of 

 "liquefaction", gumming rnd so forth); 



