PROCEEDINGS OF THE CLUB 41 



The meeting was called to order at 4 :40 p.m. by President Levine. Forty- 

 five members and friends were present. The minutes of the preceding meeting 

 were approved as read. 



The scientific talk was presented by Father Berger, who discussed "Ex- 

 perimental Studies on the Cytology of Allium" illustrating his talk with charts 

 and slides. The abstract of the paper follows : 



Root tips of Allium cepa were treated with the following chemical agents : colchicine, 

 acenaphthene, veratrine, sulfanilamide, chloral hydrate, benzene, oxygen lack and alpha- 

 naphthalene-acetic acid. The cytological effects of these treatments were noted and com- 

 pared with the well known colchicine effects. The results are summarized in the following 

 chart. 



Effect on Mitosis in Allium 



Delayed div. Diplo- Inhibition Polyploid Polyploid 

 Treatment of SA-region chromosomes of spindle cells mitosis 



Colchicine ++ ++ + + + 



Acenaphthene ++ • ++ ++ ++ + 



Veratrine + + + + + + 



Sulfanilamide + + + + + 



Chloral hydrate + slight + long ++ + + 



Benzene + + + ~f + 



Oxygen lack slight poorly + + 



developed 



Naphthalene-acetic acid meristem — — — — — 



reg. of tetra- — + + + 



elongt. chromosomes 



The first seven agents all induced polyploidy and produced the same type of cytological 

 effects in spite of the great difference in their molecular structure. The tentative conclusion 

 was drawn that the chief effects are not specific to the particular chemical agents but are 

 general effects common to all the substances in question and interfering with some meta- 

 bolic process concerned with the formation of the spindle and the division of the SA-region. 

 Benzene has the added property of rendering the structure of prophase chromosomes ex- 

 ceptionally clear so that half chromatids can readily be seen. 



Naphthalene-acetic acid differs from all the other agents used in that it has no effect 

 on the formation of a spindle. It produces polyploid cells by an entirely different process. 

 There is no effect on the meristem but differentiated cells of the cortex undergo a double 

 reproduction of their chromosomes in the resting stage. At metaphase tetrachromosomes are 

 formed and two successive divisions of the SA-regions occur. 



After a general discussion of the paper, the meeting was adjourned at 5 :50 

 p.m. to permit the audience to inspect the microscopic mounts showing the cy- 

 tological effects discussed by Father Berger. 



Respectfully submitted. 



Honor M. Hollinghurst 

 Recording Secretary 



