: The Kansas University science bulletin Vol. I No. 8 September 1902 by Various Editor - Science Periodicals

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PUBLISHED BY THE UNIVERSITY,

LAWRENCE, KAN.

Price of this number, 50 cents.

Entered at the post-office in Lawrence as second-class matter.

KANSAS UNIVERSITY SCIENCE BULLETIN.

THE SPERMATOCYTE DIVISIONS OF THE LOCUSTIDAE.

BY C. E. M'CLUNG.

Under the title, "A Peculiar Nuclear Element in the Male Reproductive Cells of Insects" , I published a preliminary account of the process characterizing the maturation divisions of the Locustidae. This was of a general character and served merely as a basis for a description of the accessory chromosome in these cells. It is my present intention to give a detailed history of the spermatocyte divisions occurring in this family, after the manner followed previously in considering corresponding stages in the Acrididae . Besides giving this account of processes, however, I shall be able to draw some comparisons between the two families. Eventually I hope to complete such a comparative study of all the Orthopteran families. Material for this larger investigation is now partially on hand, and is being added to as circumstances permit, so that it may be possible to carry through a study of the maturation stages in this order of insects within a few years.

The value of comparative cytological study was urged by Vom Rath , and its importance in relation to the accessory chromosome and the maturation mitoses received recognition in both my earlier papers . Recently Montgomery has added his influence to the movement.

For the fixation of material used in these studies, it has been found that the osmic acid mixtures of Flemming and Hermann are the most generally applicable and are productive of the best results. In connection with these, however, Gilson's acetonitric-sublimate mixture has been tried, and frequently affords an excellent fixation. Extensive shrinkage in the melted paraffin is sure to follow the use of sublimate mixtures unless celloidin is used to support the soft tissue. This double infiltration of celloidin, followed by paraffin, has been found the best method of securing clear and accurate figures, for, because of the lessened shrinkage, the elements are not crowded together and rendered indistinct. This circumstance is particularly fortunate in the case of the Locustid cells, where the nuclear elements are so numerous and crowded.

The stains employed are the iron-haematoxylin of Heidenhain and the safranin-gentian violet-orange combination of Flemming. For general purposes, nothing excels the haematoxylin stain, but it is frequently advantageous to trace the chemical changes undergone by the different cell elements in the process of mitosis, and the aniline stain above mentioned serves excellently for this. Kernschwarz has also been found a valuable stain for some purposes.

The terminology as outlined in a former paper will be followed in the present one.

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