The activated half-disk was invariably the first to become narcotized, the muscles in these, as in all other experiments involving anesthetics, being less resistant to such agents than the sense-organs.
The activated specimens, when once their pulsations had ceased, were incapable of again taking up pulsation unless stimulated to activity by artificial means. The active specimens, even after having been quiescent for several hours, would take up pulsation within 2 minutes after being put into fresh sea-water.
When such experiments were carried on in daylight narcosis would not be produced during the first day, because of the redUction of the amount of in the water by the photosynthetic activity of the sooxanthelle.
The disks were quickly narcotized on being put into sea-water to which had been added enough to change the hydrogen-ion con centration to that shown by the water in the jars in which the half disks had ceased pulsating. It seems apparent, therefore, that narcosis had been caused entirely by the increase in and not by accumula tion of other waste products of metabolism, or by a decrease in the amount of oxygen available for respiration.
Table 11 shows the results of a typical experiment for determining the total metabolism of active and activated halves of the same disk. The hydrogen-ion concentration is given in terms of the numbers of Sorensen. The sea-water at the beginning of the experiment had a hydrogen-ion concentration of = 8.1 (C. = 0.793 These experiments were not carried out in sufficient detail to deter mine the regular course of respiration or the normal respiratory quotient under the influence of varying hydrogen-ion concentration, their aim being to determine the influence of the sense-organs on the rate of total metabolism.
The differences due to muscular activity conform to those obtained from the measurements of rate of regeneration and loss of weight during starvation. The amount of respiration of an active half-disk was invariably as great as its activated mate in spite of the great differences in muscular activity. Indeed, in only a very few instances did the normal active specimen show as low a production as the more rapidly pulsating activated half of the same disk.
The activated half-disks were narcotized when the hydrogen-ion concentration of the sea-water in which they were contained had reached about 0.126X (P„ = 7.9). In fact, a greater concentra tion of hydrogen ions was seldom reached in the water in which the activated disks were kept, as after the animaIR had been sufficiently narcotized to cause the cessation of pulsation other metabolic activities were also interfered with to such an extent that respiration practically ceased. Active half-disks were capable of maintaining at least inter mittent pulsation until the hydrogen-ion concentration had become 0.159 (P,„ =7.8). Nearly all the determinations of the H con centration were made by means of color comparison with tubes of known H concentration prepared by Hynson Westcott & Dunning, from buffer mixtures standardized by J. F. McClendon, containing mixtures of phosphates and borates using thymolsulfonephthalein for concentrations above P.= 8 and phenolsulfonephthalein for concen trations below P„-= 8. These tubes were in no part of their range graduated more closely than P„=0.1, so that no very fine readings could be obtained except by estimating fractions of this unit, which could not be done with any considerable degree of accuracy.