ON TEMPERATURE AND THE BREATHING RHYTHM OF CANIS MUSTELUS AND SQUALUS ACANTHIAS

¹ From the Laboratory of General Physiology, Harvard University, Cambridge, Massachusetts

The temperature characteristic or critical thermal increments (µ) for the movement of the spiracles and gill slits in the dogfish Mustelus canis (and Squalus acanthias) are 8,200; 16,400 and 35,000 calories. Critical temperatures are found at 14.5° C. and at 20.5° C. The latitude of variation of the measurements varies in a definite way and this is correlated with the occurrence of a critical temperature of 14.5° C.

The reactions controlling breathing movements seem to be catenary processes, one of which may be concerned with the central nervous control of the breathing movements, over a certain range of temperatures.