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 citra,te-, 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 heemolytic 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 is 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. 



' " On the Effects of "Wounds Inflicted by the Spurs of the Platypus," 

 Proceedings of the Boyal Society of Tasmania, 1876. 



