86 Equisetaceae [CH. 
toxic symptoms induced by Horsetails were due to Silica or to Aconitic 
acid the latter a substance found by Matz and Ludwig. The conclu- 
sion come to by Weber, however, was that the poisoning by E. palustre 
is of an organic character, not due to silica. The young shoots, which 
contain little silica, were found in general to be much more poisonous 
than the old plants, which contain much silica. It was long since found 
by Wiggers that dried plants of E. palustre contained 8-88 per cent, of 
silica, but all species contain this substance in greater or less degree, 
and it varies considerably in amount, even in the same species. The 
feeding experiments conducted by Lohmann, with certain species of 
Equisetum, and the observed symptoms of illness after the consumption 
of some of them, particularly E. palustre, serve to show that the ill 
effects are neither to be attributed to greater or less digestibility, nor 
to the silica present. Neither are the aconitic acid and other organic 
substances, in part found in previous investigations, responsible for the 
poisoning. However, an active compound named Equisetine, a substance 
belonging to the alkaloid group, was isolated; this occurs usually, 
perhaps only, in E. palustre, at any rate in sufficient quantity to be 
dangerous to animals. Lohmann then, following up the investigations 
of Paiicerzynski, Matz, Meyer, Weber and others, ascertained definitely 
that E. palustre contains an alkaloidal nerve poison, to which the name 
Equisetine was given, and the experiments were held to decide that this 
is the poisonous substance in this species. (As stated above, E. arvense 
was held to be harmless.) 
Symptoms. At first, excitement and anxiety, followed by uncer- 
tainty of movement, reeling and staggering; paralysis of hind limbs 
at least, falling, possibly general paralysis, insensibility to external 
irritants, unconsciousness, and coma. Pulse accelerated, appetite at 
first normal, but in course of time great disturbance of nutrition ; sugar 
in the urine. Course sometimes very acute, death occurring in a few 
hours, but sometimes protracted (two to eight days), and at times even 
chronic (one to several weeks). 
In cattle, after excessive eating, continuous diarrhoea is character- 
istic, with paralysis ; while, if the food be persisted with, cachexia and 
hydrsemia combined with weakness bordering on paralysis make their 
appearance (Friedberger and Frohner, via Pammel). In addition to 
cachexia, Pott also mentions colic, stoppage, bloody urination, abortion, 
and loss of teeth. 
Young animals appear to succumb sooner than older ones, while 
grain-fed animals are more resistant than others. Referring to E. 
