Porson PLants. II 
Hence, a common fault in newly opened districts should be avoided: it is 
tc clear away all timber indiscriminately without regard to the acreage 
which the occupier can reasonably expect to keep in good condition. Any 
poticy which, for the sake of the immediate present, tends to favour future 
trouble with weeds is a short sighted one, and such statements as that 
Saffron Thistle, for instance, instead of decreasing the carrying capacity 
of the land had precisely the opposite effect, are likely to do serious harm 
unless strenuously contradicted. Only a mistaken self interest could 
dictate so obvious a mis-statement, but unfortunately apologists are not 
wanting for the majority of our most obnoxious weeds. 
Poison Plants. 
In regard to poisonous plants, all those which contain undoubted 
poisonous principles in such quantity and condition as to be openly dan- 
gerous to man or animals are marked thus :— ee" 
In very many cases, however, considerable doubt exists as to whether 
plants supposed to be poisonous are really so, and it is exceedingly difficult 
to obtain exact information in*such cases. The poisonous qualities are 
usually greater when a plant is in flower or fruit than when it is in leaf, 
and hence a poisonous plant may not be detected for some time, especially 
if stock reject it as soon as it begins to flower. On the other hand, starved 
or travelling stock when suddenly turned into rich luxurious pasture are 
peculiarly apt to gorge themselves and to suffer in consequence. The 
mere change of pasture often has a similar effect, although in many cases 
the stock suffer or die by eating plants new to them which they have not 
as yet learnt to avoid by experience. 
Again, when stock are starved or have abnormal appetites as often 
obtains in breeding or milking cows, they may suddenly take to devouring 
plants and other objects which are injurious to them and which they had 
previously learnt to avoid. Finally, plants when diseased or affected by 
fungi may become injurious although normally quite innocuous. Hence, 
il is exceedingly difficult or impossible to draw a definite line of demarca- 
tion between poisonous and non-poisonous plants. The usual crigin of 
the report as to the poisonous character of a plant is that some stock die, 
and the nearest plant is selected as the scapegoat, without any post mortem, 
experiment or investigation of any kind. In some cases, this is done pur- 
posely when the stock have really died from anthrax or similar diseases. 
On future occasions, it is usually easy to find the suspected plant somewhere 
near where the stock have been, and so reports continue to come in. If 
the plant cannot be found, then some other plant is credited with poisonous 
properties. 
Such reports were accepted with almost childish faith by Mueller and 
even by later authorities, and as a consequence some harmless plants of 
slight but undoubted fodder value are widely reported to be poisonous, and 
of the total recorded as poisonous probably not one-third are actually so. 
The only possible definition of a poison plani is that it is one of which 
small] doses exercise some internal, irritant narcotic, or chemical action 
on the animal which produces serious or fatal consequences either directly, 
or as the result of an after-effect or’ cumulative action. To class woody 
or fibrous indigestible plants as poison plants because stock may die, when 
forced by hunger to eat them, is ridiculous. We might as well class leather 
as a poison because a man forced to eat leather by hunger is likely to suffer 
seriously in consequence. So long as stock are well fed such ‘‘ poison’ 
plants ’’? do harm only by taking up-the room of more nutritious ones. Tn 
