The acid oxalates seem especially harmful to sheep, causing loss of appetite, exhaustion, small and scarcely perceptible pulse, rapid breathing, and constipation, and in many cases severe diarrhœa, uncertain gait, and sometimes death (Müller).
The milk of affected cows is with difficulty made into butter (Pott).
REFERENCES.
[73], [141], [190], [203], [233].
Polygonum sp. Several species of Polygonum are said to have poisonous properties. The chief among them is Buckwheat (P. Fagopyrum), the grain of which is widely grown as a food for both man and live stock. This plant, particularly the flowers, has given rise to a well-known rash in man, cattle, sheep, and pigs, with congestion and tumefaction—especially of the head and ears. There is also nervous disturbance, with agitation and hallucination—sheep, for example, may butt against objects. The affection of the nervous centres may lead to fatal results, which have followed in cattle, sheep, and pigs. Little is known of this so-called Fagopyrism, but after analytical and spectroscopical researches on the colouring matter of the tegument Kurt concluded that it is due to the chlorophyll.
Persicaria (P. Persicaria L.) and Water-pepper (P. hydropiper L.) are also stated to be harmful, though the former has been considered a nutritious plant and has been given to horses and cattle as a green food.
Both species, however, are said to cause a rash, and to contain injurious narcotic substances. Persicaria is stated by Müller to have caused inflammation of the bladder and the digestive tract in pigs, and Water-pepper to have caused hæmaturia; fatal results have followed. Pott records similar symptoms. In regard to Persicaria it should be noted that it varies considerably in general form, and may possibly vary also in acridity. Bentham and Hooker state of P. hydropiper that “the whole plant is more or less acrid or biting to the taste.”
REFERENCES.
[17], [19], [73], [190], [204], [213].