VENOMS IN THE ANIMAL SERIES 325 
thanks to the acquisition of a small supply kindly forwarded to me 
by C. J. Martin. Noc proved that it possesses in vitro certain 
properties of snake-venoms; like the venom of Lachesis lanceolatus, 
it induces coagulation in citrate-, oxalate-, chloridate-, and fluorate- 
plasmas. Heating at 80° C. destroys this coagulant power. 
Contrary, however, to what is found in the case of the venoms 
of Vipera and Lachesis, the secretion of Ornithorhynchus is devoid 
of hemolytic and proteolytic properties. 
Lastly, its toxicity is very slight, at least five thousand times 
less than that of the venoms of Australian snakes. A mouse is not 
even killed by 5 centigrammes of dry extract, and in the case of 
the guinea-pig 10 centigrammes only produce a slight painful 
oedema. 
It has been remarked that the volume and structure of the 
poison-gland exhibit variations according to the season of the year 
at which it 1s observed. It is therefore possible that these 
variations also affect the toxicity of the secretion (Spicer). 
By certain authors the poison of Ornithorhynchus is considered 
to be a defensive secretion of the males, which becomes especially 
active in the breeding season, and this hypothesis is plausible. 
In any case it would seem that as a venom the secretion is but very 
slightly nocuous. 
It will have been seen from the papers quoted above that the 
chemical nature and physiology of the various venoms, other than 
those of snakes, are as yet little understood and need further 
investigation. 
The main outlines of this vast subject have scarcely been traced, 
and the study offers a field of interesting investigations, in which 
the workers of the future will be able to reap an ample harvest of 
discoveries, pregnant with results for biological science. 
1 “On the Effects of Wounds Inflicted by the Spurs of the Platypus,” 
Proceedings of the Royal Society of Tasmania, 1876. 
