The Handling of Chromosomes

Abstract

THE study of chromosomes is a branch of biology which has expanded very considerably in the last fifty years and has recently acquired an extended popularity owing partly to its association with genetics and partly to an increased technical facility which has been gradually built up from the accumulated experience of many workers. The modern microscope, perfected at the end of the last century, and the use of the microtome were understood before the War of 1914-18 and have not been improved appreciably since. On the other hand the last twenty-five years have added the smear techniques associated with the use of rapid and transparent (but often transient) stains, which can also be applied to extend the use of the microtome to very thick sections. Some improvements have been made in the formulae of fixatives and, for certain purposes, by using reagents such as acetocarmine and rapid macerating treatments involving hydrolysis with hydrochloric acid, it is now possible to see in a few minutes things which a generation ago would have necessitated a delay of several days. In other cases whole fields of new observation have been opened up by the development of special methods such as those now available for the demonstration of spiral structure. The most recent innovation, and one which is certain to be further extended in the future, is the application of specific chemical reactions such as selective digestibility and microchemical colour tests such as Feulgen's reaction to the study of chromosome structure.

The Handling of Chromosomes

C. D. Darlington L. F. La Cour. Pp. 166 + 16 plates. (London: George Allen and Unwin, Ltd., 1942.) 8s. 6d. net.