_R. sceleratus_ L., or Celery-leaved Buttercup, is probably the most toxic species, and it is stated that in man a single flower may cause poisonous symptoms resembling those due to _Anemone_ and _Colchicum_. It is considered especially dangerous to cattle, and has caused many losses: among its French names are _Mort aux Vaches_, and _Herbe sardonique_. Poor people have been known to eat the young shoots when boiled, heat dispelling the poison.
_R. Flammula_ L., the Lesser Spearwort, has repeatedly proved fatal to horses and cattle.
_R. bulbosus_ L., the Bulbous Buttercup, is somewhat variable in toxicity, and is least dangerous after the flowers have dropped their corolla, and the bulb-like rootstock is most harmful in autumn and winter. The flowers are the most dangerous part.
_R. Ficaria_ L., Lesser Celandine, varies in toxicity with locality and season, being most harmful at the flowering period. It is stated that wood-pigeons eat the roots with avidity, and that the young shoots have been eaten as a salad in Germany, as they are not toxic. An English veterinary surgeon (Flower) recorded that three heifers were poisoned by it (_Vide_ Cornevin).
_R. acris_ L., Acrid Buttercup or Tall Crowfoot, is a frequent cause of poisoning in cattle, and Cornevin says it is perhaps the species which causes the most accidents.
_Toxic Principle._ The buttercups contain an acrid and bitter juice, the chemical properties and composition of which are not well known, but it is believed that the substance is identical with the _Anemonin_ of the _Anemone_ sp. (_q.v._). Beckurts isolated _Anemonin_ and _Anemonic acid_ from _R. acer_. Pott, however, states that the poisonous species contain the two alkaloids _Aconitine_ and _Delphinine_.
_Symptoms._ The buttercups are acrid, burning and narcotic, causing irritation of the mucous membrane, with inflammation of the intestinal tract.
Cornevin shows that _R. sceleratus_ induces gastro-enteritis, colic, diarrhœa with excretion of black foul-smelling fæces, vomiting when possible, falling-off in milk yield in cows, nervous symptoms, reduction in pulse, and stertorous respiration, dilation of the pupils, enfeebled condition, difficult mastication, spasmodic movements of the ears, lips, etc.,—followed in serious cases by convulsions, sinking of the eye in its socket, possibly stoppage, and death in 6 to 12 hours after convulsions first appeared.