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 

 efiects 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 Paucerzynski, 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, insensibihty 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. 



