302 TUMORS. 



suggested by Hansemann ' and others that these alterations may be due 

 to a loss of differentiation in the tumor cells and the assumption of a 

 more independent existence. This condition has been called Anaplasia, 

 and while the term characterizes an important series of facts, it leaves 

 them unexplained. 



Thus it is still uncertain whether the removal of mechanical or other 

 restraints to cell growth and proliferation ; or the acquirement of new 

 capacities through retrograde differentiation or reversion ; or the action 

 of some as yet unknown "formative stimulus," are, either individually or 

 collectively, and if so in what degree, concerned in the origin of tumors. 5 



A more subtle and perhaps more comprehensive view of the agencies which must 

 be taken into the account in the excitation of tumors is that especially advocated by 

 Weigert 3 and Ribbert. 4 These observers and those in sympathy with their views do 

 not admit a new formative stimulus into their conception of the origin of tumors, but 

 regard the usual potencies of the cells in this respect to be sufficient if the natural re- 

 straints to over proliferation be in any way diminished. 



Ribbert has perhaps more definitely than any other framed a working hypothesis 

 along these lines which is at least suggestive. He lays stress in his conception of the 

 origin of tumors upon the intimate associations of the cells of the normal body as parts 

 of an organism, whose varied capacities are normally held in some fashion under mutual 

 restraint in subservience to their common welfare. This mutual relationship, hosvever, 

 once destroyed, for example, by the separation of cells or cell groups from their organic 

 associations, they assume less highly differentiated characters, their physiological capac- 

 ities are no longer held in leash, and these, if the nutritive and other conditions be 

 favorable, may express themselves in exaggerated fashion by excessive growth and 

 proliferation. 



Ribbert explains the way in which he conceives that the process of cell disassocia- 

 tion and release from restraint may occur. Since he does not admit a primary increase 

 in the inherent proliferative capabilities of the cells, he cannot assume, as is commonly 

 done, that the process is initiated, in carcinoma for example, by the epithelial cells. 

 He assumes that the process may start in the connective tissue, which is liable to in- 

 crease in amount in response to a variety of influences, notably those which involve 

 trauma, or simple inflammation, or replacement hyperplasia. In the starting of carci 

 noma of the stomach or intestine, for example, Ribbert asserts that, in many cases at 

 least, the new- formed connective tissue cuts off cells or cell groups from their organic 

 connections, and claims that in this way alone we may account for the required release 

 from the restraints of the organic association and the exuberant aberrant growth which 

 follows. 



This view is interesting in connection with the frequent association of carcinoma 

 with chronic inflammation, which has been already noted. While obviously vague and 

 open to many objections, and apparently applicable to but a small group of tumors, 

 and while not yet confirmed by experimental results, this view, nevertheless, perhaps 

 indicates the lines along which fruitful research may be expected. 



1 Hansemann, "Die mikroscopische Diagnose d. bosartigen Geschwulste," Berlin, 



1897, see also resume and bibliography by Aschoff, Lubarsch and Ostertag's "Ergeb 

 nisse," Jahrg. v., 1898, p. 22. 



2 For a resume of some recent studies on atypical mitosis in tumors see Farmer, 

 Nature, Feb. 4th, 1904; also Bashford and Murray, Proc. Roy. Soc., January 21st, 1904. 



3 Weigert, "Neue Fragestellungen in path. Anat.," Deut. med. Wochenschr., 1896, 

 p. 635. 



4 Ribbert, Deut. med. Wochenschr., 1895, Nos. 1, 2, 3, and 4, bibl. ; also ibid., 1896, 

 No. 30; also "Das patholog. Wachsthum der Gewebe," Bonn, 1896. See for opposing 

 views the monograph by Lubarsch, "Zur Lehre v. d. Geschwillsten u, Infectionskrank- 

 heiten," Wiesbaden, 1899, p. 306, bibl. ; also Ziegler, Munch, med. Wochen., March 8tb, 



1898, p. 312. See also bibliography of cell regeneration in Fuerst, Ziegler's Beitrage, 

 etc., Bd. xxiv., p. 454, 1898, and reference to Aachoff above. 



