[586] Digitoxin (see ante, [p. 420]) belongs to this group.
Dr. Fraser considers, from his experiments, (1) That strophantin acts primarily on the heart, producing, as an end result, heart paralysis, with permanence of the ventricular systole. (2) He found the pulmonary respiration to continue in cold-blooded animals many minutes after the heart was paralysed. (3) The striped muscles of the body are affected, and twitches occur in them; their tonicity is exaggerated, and finally their functional activity is destroyed. This change is referred to an action on the muscular structure itself, independent of that upon the heart, and also independent of the cerebro-spinal nervous system. (4) The reflex action of the spinal cord is suspended after the heart is paralysed, but the motor conductivity of the spinal cord and of the nerve trunks continue after the striped muscles of the body are paralysed. (5) The lymph-hearts of the frog continue to contract for many minutes after the blood-heart has been paralysed.
§ 556. Apocynin.—In the root of Apocynum cannabinum a non-crystallisable substance, soluble in alcohol and ether, but not soluble easily in water, has been separated and found to have a physiological activity similar to that of the digitalins.[587]
[587] Hardy et Callois, “Sur la matière active du Strophanthus Hispidus ou Inée,” Gaz. Med. de Paris; Pelikan, Compt. Rend., t. 60, p. 1209, 1815; Sharpey, Proc. Roy. Soc., May, 1865; Fagge and Stevenson, Pharm. Journ., p. 11, 1865-66; Fraser, Journ. of Anatom. and Phys., also Proc. of Roy. Soc. of Edin.; Poillo and Carville, Arch. de Physiol. Norm. et Pathol., 1872; G. Valentin, Zeitschr. et. Biologie., x. 133, 1874.
3. NON-CRYSTALLISABLE GLUCOSIDES ALMOST INSOLUBLE IN WATER.
§ 557. Scillain, or Scillitin, a glucoside which has been separated from the bulbs of the common squill. It is insoluble or nearly so in water, but easily dissolves in alcohol. It is little soluble in ether. It acts upon the heart, and is poisonous.