The chromosomes / by M.J.D. White.

  • Michael James Denham White
Date:
[1961]
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: The chromosomes / by M.J.D. White. Source: Wellcome Collection.

    9/144 page V
    INTRODUCTION I HOPE that this book will be of use to many bio¬ logists who realize that chromosome-cytology has made considerable progress in the last ten years, and that the existing text-book accounts of mitosis and meiosis are hopelessly inaccurate, but who have no time to read the larger works of Darlington and Bëlaf, which must remain the standard sources of information on the subject. Chromosome cytology is essentially a practical sub¬ ject, which can only be thoroughly mastered by a study of actual preparations under the microscope. Unfortunately this study is usually regarded as too difficult to be included in a degree course in biology. It is surprising, however, how much can be seen, even without using an oil-immersion objective, provided that one chooses suitable material with large chromo¬ somes. There is no doubt that for most purposes the testes of Locusts and Grasshoppers (any species will do) provide the best introductory material. They should be fixed in Flemming's solution and stained in one of the aniline dyes like Gentian Violet. In the course of the past year I have made the ordinary degree students in this department work through material of this kind (sectioned at 25/x so as to obtain whole nuclei). They were able to see all the stages of mitosis and meiosis and even to work out the average number of chiasmata per nucleus in three different species. That it is possible for students to do this in a course involving only one afterkioon a week should destroy the myth that cytology is a fantastically difficult subject. In a book of this size it is necessarily not possible
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