318 Maas, Eiuführuug iu die experiineutelle Entwickelungsgeschichte. 



On Nuclear divisions in Malignant tumours 

 a reply to Prof. v. Hanseinann, by J. B. Farmer. 



In the Biologische Centralblatt of March. 1, 1904. Prof. v. Hanse - 

 mann complains that justice has not been clone to theviews already 

 published by him, in tlie course of a preliminary note by Mss''* 

 Moore and Walker and myself on „bösartige Geschwülste". 



Prof. V. Hansemann seems to lie under a misconception as 

 to the scope of the work in this paper. Our investigations have 

 led US to the conclusion that a reduction-division similar in cha- 

 racter to that known as heterotype in animals and Plauts occurs 

 in the cells of malignant growths. This is followed by homotype, 

 and subsequently by more irregulär mitoses. We regard the essential 

 change that occurs when a cell takes upon itself the characters leading 

 to the formation of a malignant growth as involving a transfor- 

 mation of somatic into reproductive or generative cells which sooner 

 or later go through the reduction divisions. The pathological re- 

 sults attendant on such a transformation are due to the uncoordi- 

 nated relations thus instituted. Now Prof. v. Hansemann has given 

 quite another explanation of the processes. „Erstens durch asym- 

 metrische Mitosen und zweitens durch Zugrundegehen einzelner 

 Chromosomen." The essential difference between his view and our 

 own may be expressed shortly by saying that we regard the malignant 

 tissue as having arisen in a manner quite comparable with that 

 in which normal reproductive cells arise, whilst Prof. v. Hanse - 

 mannn ascribes the differences in nuclear characters to something 

 foreign to the ordinary cell processes in the individual affected 



The difference between us is a fundamental one. 



As our paper was only of the nature of a preliminary com- 

 munication (it is so stated in the text), it would have been obviously 

 out of place to have discussed the vievs advanced by Prof. v. Hanse- 

 mann as well as of others whose opinions also are divergent from 

 those which we have been led to adopt. We hope however in a 

 memoir, now in preparation, to compare fully the results of others 

 with our own. In the meantime we do not propose to engage 

 further in purely controversial correspondence. [42] 



& 



O. Maas. Einführung in die experimentelle 



Entwickelungsgeschichte (Entwickelungsmechanik). 



Das unter obigem Titel bei Bergmann in Wiesbaden erschienene 

 Buch beabsichtigt, wie sein Titel angibt, eine Einführung in die 

 Probleme der experimentellen Entwickelungsgeschichte zu sein. 

 Man sieht dem Buch an, dass es aus praktischen Bedürfnissen 

 heraus entstanden ist. Es ist, wie der Verfasser sagt, aus Vor- 

 lesungen hervorgegangen, die vor Anfängern gehalten wurden und 

 für einen derartigen Leserkreis ist es wohl auch in erster Linie 

 bestimmt. Man wird anerkennen müssen, dass der Verfasser dieser 

 Aufgabe in hohem Maße gerecht wird. Er beschränkt sich durch- 

 aus auf das Tatsächliche und vermeidet überflüssiges Theoreti- 



