Pathogenesis :

    Tarentula is a venomous Tropical Spider. The sphere of action is mainly on central nevous system, genitals and blood.
I.     Cerebro-spinal system: Chorea, Hyperesthesia.
II.   Circulation (Heart, Arteries): Contraction of vessels
III.  Generative Organs: (especially of women) Neuralgia
IV.  Blood (T.cubensis): Toxaemia, Anthrax, Gangrene.

Action on heart:
1.     It causes cramps of circular fibres of heart, like cactus, Iodine, Kali carb, Lachesis, Digitalis etc, it differs from them in producing contractions of the spiral fibres.
2.    The spiral fibres end in the columnae carneae & hence influence the papillary muscles, thus causing various murmurs.

I. Cerebro-spinal Nervous System: