Nucleus and Chromosomes 27 



During that period, a certain ninnber of nuclei undergo degeneration. . . . 

 Alter tliat period . . . cells . . . (oniplete their di\ision. . . . The achromatic 

 figure becomes visible. . . . Chromosomes move toward the poles. . . . Cyto- 

 plasmic division is completed. . . . Some mitotic figures of too great size . . . 

 and some pluricentric divisions remain as a testimony of the nucleotoxic 

 eliect. . . .* 



These basic statements require no change today even though knowl- 

 edge lias expanded in many cHrections. Admittedly, as the basic idea 

 becomes extended and broadened, additional points are added. For 

 example, the c-mitosis illustrates enlargement of the original ex- 

 planation, but no radical changes in concept arc necessary."''' 



The Dustin school did not limit their work to animal cells. A 

 Himgarian scientist, the late Dr. L. Havas, treated Alliuiii root tips 

 with colchicine.-" His slides were a part of the Dustin collection 

 available to the authors in 1949. Since the arrested metaphase or 

 c-mitosis was so clearly preserved, new photomicrographs were made 

 (Fig. 2.1C), showing the increase in numbers ol chiomosomes, large 

 restitution nuclei, and "achromatic spheres." ^" ' Btit the original 

 text by the Brussels investigators did not mention the polyploid con- 

 ditions ol these cells. ••^ 



Independently, iri 1937, the senior author tested cells from treated 

 root tips (Fig. 2.\A and B) with acetocarmine methods; the tests 

 showed that polyploidy was created in many different areas of the 

 A Hi II III root. I he Brussels material and that used at Cold Spring 

 Harbor (cf. ChajJter 1) were, in every respect, similar. -^^ 



A third and independently conducted test with Alliiini roots and 

 colchicine was reported by Dr. Pierre Gavaudan and associates. They 

 published the first account of polyploidy induced by colchicine in 

 ftme, 19.87. Their rei)ort stated:^^ 



It is evident that in these cases there is a separation of pairs of chromosomes, 

 the lumiber of chromosomes of a restitution nucleus is double the normal 

 nimil)er. The chromosome list of Gaiser indicates that 2n-16 occin-s in Allium 

 crfxi. Our residts show "pseudomitoses" with more than thirty pairs. f 



This original report and its significance were not mentioned in 

 reviews-*^' ^'^ or papers-""'^ in the period immediately following its publi- 

 cation. The more dramatic demonstrations that dealt with induction 

 of j)Cjlyj)loidy in plants overshadowed the original and what is now 

 realized as a classic ptdilication by the Gavatidan schocjl. 



As soon as Dr. .Albert Levan returned to Sweden from America 

 in the autumn of 19-i7,''" experiments with Alii inn roots and colchi- 

 cine were started. This material formed the basis for his concept of 

 an arrested metaphase, as a cole hie ine-mitosis.''" Remarkable simi- 



* A iranslalion of pertinent coiiimeiUs tioni tlic aiii(le cited in Reference No. 

 12, Chap. I. 



t Iranslatecl from paper written in French 1)\ authors tiled in Reference No. 

 20. C'.liap, I. and Rcfeieiuc No. 11 of tliis chaptei. 



