Abstract
A device was invented for recording pulsation of the dorsal vessel in intact insects. A constant light beam projected on the heart or the aorta of the dorsal vessel through the middorsal cuticle was reflected on the photo-cell in a pick-up. Direction of the reflected light beam, as being fluctuated by pulsation, was detected by photoelectric effect of the photo-cell and its change was converted to the potential difference. The potential change amplified to record a mechanocardiogram with the pen-writing oscillograph. The pick-up was a bridge and consisted of two constant 50K ohm each, and one variable resistance and photoconductive element. A CdS-cell was used instead of the photo-cell in the previous work. The mechano-cardiograms recorded with the present new type pick-up were essentially the same as those done with the old one. However, the new pick-up was more effective in recording the mechanocardiograms of the larvae, pupae and adults of Bombyx mori, Dioryctria splendidella, Sphingidae sp., Lucanus maculifemoratus and Hyphantria cunea, because of its compact size, low power consumption and high sensitivity; 14 to 17 times as sensitive as the old one.
