607 
which are not always within ready range of observa- 
tion, or, perhaps, even involved in mystery, such as 
physiology and chemistry have hitherto striven in vain 
toclearaway. Theso-called Cape Weed, for the pres- 
_ence of which I am not responsible, as it had already 
_irrepressibly invaded some partsof Australia as early 
as 1833 (Cryptostemma calendulaceum), was recently 
subjected in my laboratory to examination, with a 
_view of ascertaining whether any chemically separa- 
ble active principle might produce the violent purg- 
ing, terminating in acute and often fatal dysentery, 
to which flocks occasionally become subject, but the 
investigation gave negative results. ‘The deleterious 
effect arises, therefore, either merely from mechanical 
irritation and distension, when sheep have gorged 
themselves with this weed, or it may be traceable to 
a locally - developed poison, which, in ordinary cir- 
cumstances, does not exist. The latter was ascertain- 
ed to be the case by my own experiments as far as 
Swainsona Greyana, Swainsona lessertiefolia, Lotus 
Australis, Gastrolobium bilobum, and, perhaps, Sty- 
pandra glauca, are concerned. The two former cause 
in some localities cerebral affections in horses and oth- 
er pastural animals, terminating in death ; but thecul- 
tivated plants were found harmless. Gastrolobium, 
with some species of Oxylobium and Isotropis, the 
bane of the heath pastures of West Australia, has 
hitherto baffled all efforts to detect an antidote, but 
one of the most dreaded species, Gastrolobium bilo- 
bum, proved here, in cultivation, inert. Desert speci- 
mens of Lotus Australis produced, in my local trials, 
deadly effect on sheep; while our garden - plant, or 
the fresh herb from the sand - shores of Port Philip. 
