vi] Gframineae 83 
killed by giving it 2 kilogrammes (4-4 Ib.) of Darnel. Cornevin concluded 
that the amounts of Darnel necessary to kill certain animals would be 
as follows: 
Horse 0-7 Ib. per 100 Ib. live weight. 
r Ruminants . . . . 1-5 to 18 Ib. per 100 Ib. live weight. 
Poultry . . . . 1-5 to 1-8 Ib. 
Dog 1-8 Ib. 
He found pigs very little affected. As regards man 30 grammes 
(1 oz.) of the flour appear to be about the most that can be taken without 
showing dangerous symptoms. 
The presence of Darnel flour in flour of the cereal grains may be 
determined by an examination of the starch granules, which are given by 
Cornevin as only 5 to 8 /z in diameter (compared with 25 to 45 JJL for 
rye), simple in general, but sometimes in groups of 2 to even 5, poly- 
hedral or partly rounded, with a nucleus or fusiform nucleal cavity, 
and readily coloured blue with iodine ; they resemble those of maize but 
are only about one-eighth the size. 
Toxic Principle. The grains only are harmful, and contain the 
narcotic alkaloid Temuline (C 7 H 12 N 2 0), which Hofmeister showed to 
be a strong nerve poison, and which is said to occur to the extent of 
0*06 per cent, in the seeds. Other authorities impute the toxic property 
to Loliine, while Smith states that the toxic principle is Picrotoxin. In 
relation to the grain fungal hyphae have usually been found, though not 
invariably, 20 to 30 per cent, of the plants sometimes being free from 
it. The fungus (Endoconidium temulentum) is propagated vegetatively 
by means of mycelium. It appears to live symbiotically in the maturing 
grain, and perhaps to a slight extent renders possible the assimilation 
of nitrogen from the atmosphere ; but Freeman observed that though 
generally stimulating to the Darnel, it is occasionally injurious to it. 
Esser sums it up by saying that according to most authorities who have 
investigated Darnel the fungus alone contains the toxic substance 
the Temuline and hence the grains in which the fungus does not 
occur should be harmless. The fungus is found in Darnel grain in all 
countries Chile, Brazil, S. Africa, Persia, Spain, France, Sweden, 
Germany, etc. So far as can be ascertained there have been no feeding 
experiments to determine the difference in toxic character between 
fungus-infested and fungus-free grains. The dangerous properties are 
said to be most pronounced in wet seasons. 
Symptoms. In France Darnel is called Ivraie, because, when brewed 
with barley, it acts as a narcotic intoxicant. 
62 
