On the effects of sulphate of atropia on the nervous system of frogs / by Sydney Ringer ... and William Murrell.

  • Ringer, Sydney, 1835-1910
Date:
[1876-1877]
Catalogue details

Licence: Public Domain Mark

Credit: On the effects of sulphate of atropia on the nervous system of frogs / by Sydney Ringer ... and William Murrell. Source: Wellcome Collection.

    6/14 (page 326)
    the motor centres and sensory nerves,” and our observation confirm this conclusion in respect of the motor centres (spina cord). Thus in the experiments we have recorded in this papei after tying the abdominal aorta, or the femoral artery an( vein, and then poisoning the animal, we found that paralysi set in as early, progressed as quickly, and became as complet< in the ligatured as in the unligatured, and consequently poisoned limb. It occurred to us that perhaps our experiments were mad' at a different time of year to those performed by other ob servers, and that this might account for the difference in ou results. Our first observations were made in May, June am July, but with the view of solving the point we repeated many of them during the month of November. We tied the femora artery and vein of the right leg of two frogs, and then poisonec them by injecting sulphate of atropia under the skin of th< left axilla. To one we gave a dose too small to produo complete paralysis; to the other a much larger dose, namely half a grain, which caused complete paralysis in two minutes In the frog to which the small dose had been administered both posterior limbs were almost completely paralysed, bu the ligatured limb was a little the stronger after the poisoning In the frog with the large dose, both hind limbs were abso lutely paralysed in two minutes. We feel bound, therefore, t< conclude that sulphate of atropia paralyses in great part by it action on the spinal cord. Does atropia exert its action directly on the cord, or only indirectly through its influence on the heart and circulation Is it a spinal depressant, or are the phenomena we hav< witnessed simply due to its action as a cardiac poison ? Atropia powerfully depresses the heart, slowing or evei completely arresting its action. Even in cases in which th< number of pulsations is reduced by only a half the heart doe very little work, for on examination it is found that during diastole it becomes but slightly distended with blood, so tha the circulation must be in reality almost at a standstill. Tha such is the case is also shown by a microscopic examination c the web of the foot, when the blood will be seen to be eithe