BOTANY: 0. J. EIGSTI nuclei. It is also well known that the mitotic spindle formed during the process functions in the separation of daughter chromosomes and plays an important r6le in the formation of a cell plate between the daughter nuclei. The cell plate marks the place where the new cell wall is laid down to separate the two daughter cells and thus completes the mitotic process. The two new cells are genetically similar to each other and to the original parent cell. Interference or interruption of any one phase or several phases of the mitotic process could bring about the production of cells that differ from each other or from the parent cell. The colchicine treat-ments interrupted or inhibited certain phases of the mitotic process and without apparently affecting certain others. Colchicine is soluble in water and effective in very dilute solutions. The solutions used in these original studies were in concentrations of 1%, 0.1% and 0.01% and applied for 24, 48, 72, 96 and 108 hours. The seeds were germinated upon moist filter paper soaked with the desired concentration of colchicine for a given interval of time. Allium bulb root tips were treated by immersion. Definite toxic effects were observed from the highest concentrations. An increase in colchicine concentration or an increase in length of time for treatment beyond 72 hours was found to be detrimental and fatal to the future development of the meristematic tissue. There was a close correlation between the production of morphological ab-normalities and the intensity and duration of the treatment. Increase in concentrations and increase in time for treatment caused increases in both structural abnormalities and cytological abnormalities. Stem and root meristems were analyzed for cytological changes by two methods, namely, the aceto-carmin smear method, and the paraffin method for preparation of permanent slides. A weak Flemming solution was used for fixation and several different cytological stains were used for staining the sections. The principal plants used in this study were Ailium cepa, Raphanus sativa, Zea mays and Triticum vulgare. The general morpho-logical and tissue changes which appearedin these stem and root meristems were all similar in character. Since AIlium root meristems offered material with large nuclei which were of advantage for cytological study this form was used most extensively for the detailed cytological studies given here. A 0.1% and 0.01% colchicine solution both produced enlargements of Allium root, and stem portions, figures lb, 2b, 3b, were consistently larger than untreated material, figures la, 2a, 3a. A decrease in the concentration ofcolchicine solution increases the length of time necessary for pro-duction of the enlargement. A fairly concentrated solution of 1% has