OBITUARIES 69

The author prefers the electrocautery to the Paquelin thermocautery when­ever cauterization is resorted to.

W. H. Crisp.

A quantitative study of achromatic and chromatic sensitivity from center to periphery of the visual field. Presented to the faculty of Bryn Mawr College in partial fulfillment of the requirements for the degree of doctor of philosophy. By Hazel Austin Wentworth. 192 pages, illustrated. Paper covers. Pub­lished for the American Psycho­logical Association by Psychologi­cal Review Company, Princeton, New Jersey.

The work included in this disserta­tion is to some extent along the lines of studies published by Ferree and Rand in the Archives of Ophthal­mology and the American Journal of Ophthalmology.

The chromatic thresholds were de­termined under light and dark adapta­tion. The achromatic thresholds were determined with a completely dark-adapted eye at the same points in the field as were used for the chromatic thresholds. Special attention was given to variations in the light and color sensitivity in the dark-adapted eye in and around the macula.

The following results of special im­portance may be mentioned here: The sensitivity to yellow in the different quadrants was found to be from 276 to 5,170 times as great at the center as at the periphery. From point to point in a given meridional quadrant and at cor­responding points in different meri­dional quadrants there were great irregularities in the ratios of sensitivity to different colors; small regions of decreased sensitivity to one color being found with no loss of sensitivity to the other colors. With a high intensity of stimulus the limits of chromatic sensi­tivity to yellow were found to be coex­tensive with those for white light vi­sion ; and at all intensities, with stimuli equalized in energy, the limits for yel­low fell outside those for red, blue, and

green. The interlacing of limits for red, blue, and green is not necessarily a pathological phenomenon but rather a characteristic relationship for the normal eye. A general tendency was found for the area of the color fields to vary with the logarithm of the in­tensity of the stimulus light. Under dark adaptation, color sensitivity was found not to extend to the periphery for all wave lengths. The retina was most sensitive to green at every point in­vestigated, and the ranking as to sensi­tivity from highest to lowest was in general green, yellow, blue, red, except that at the fovea and at a point in the nasal quadrant five degrees from the fovea the sensitivity to blue was greater than to yellow. W. H. Crisp.

Handbuch der gesamten Augenheil-kunde; sections 491 and 492, continu­ing Die Krankheiten der Orbita (Dis­eases of the orbit). By A. Birch-Hirschfeld. 154 pages, illustrated, 16.80 marks. Verlag von Julius Springer, Berlin, 1930.

This continuing section is a fragment of the chapter on diseases of the orbit, which it carries from page 895 to page 1048; the total number of pages in the whole chapter being 1048. It contains the indexes for this chapter and for the chapter on pulsating exophthalmos.

W. H. Crisp.

OBITUARIES David Nichols Dennis

On November seventeenth last ophthalmology lost one of its most highly esteemed and distinguished representatives in the death of Dr. David Nichols Dennis of Erie, Penn­sylvania. He had been in ill health some years before and had been obliged to take an extended rest, but he had recovered and resumed active practice when the end came.

Dr. Dennis was of a class of scholarly physicians, now unfortunately growing fewer, whom the medical profession can ill afford to lose. A man of fine medical attainments, thoroughly