Temperature and Frequency of Heart Beat in the Cockroach

The frequency of pulsation of the intact heart in nymphs (final (?) instar) of Blatta orientalis L. increases with the temperature according to the equation of Arrhenius. The constant micro has typically the same value, within reasonable limits of error, as that (12,200) deduced for other, homologous activities of arthropods where the rate of central nervous discharge is perhaps the controlling element, namely 12,500 +/- calories for temperatures 10-38 degrees C. Below a critical temperature of about 10 degrees a change to a higher value of the temperature characteristic occurs, such that micro = 18,100 +/-. Exceptionally (one individual) micro = 14,100 +/- over the whole range of observed temperature (4.5-28 degrees ). The quantitative correspondence of micro for frequency of heart beat in different arthropods adds weight to the conception that this constant may be employed for the recognition of controlling processes.