160 Dr Davy on the Structure of' the Heart 



have never seen any animal resembling the unicorn among their 

 paintings, but such an animal is said to exist beyond the Orange 

 River. They are fond of music and dancing, but their musical 

 instrument is rude, and without power or variety, consisting of 

 one string stretched upon a bow, whose vibrations are pnxluced 

 by the breath, with great exertion. 



The Bushman'*s conception of a Supreme Being is, that he is 

 an evil deity, and their notion of futurity, that there will be im 

 eternity of darkness, in which they will live for ever, and feed 

 on grass alone. They imagine that the sun sends rain, and 

 when he is clouded, they hold up burning wood, in token of dis- 

 approbation. They believe that the sun and moon will disap- 

 pear, to produce the darkness they anticipate. 



The Bushman''s bow is made of a peculiar tree, called the 

 Blue Bush, whose branches are almost moulded by nature to 

 the artificial form. The sinews of the quagga yield power- 

 ful bow-strings, and the arrow is formed of a slender reed, head- 

 ed with antelope'^s horn, and pointed with a small triangular 

 piece of metal, which they procure from the CafFers. 



Observations an the Structure of the Heart of Animals of the 

 genus Rana. By John Davy, M. D., F. R. S. Communi- 

 cated by Sir James M^'Grigor, Director-General of the 

 Army Medical Board. 



JL T is commonly asserted by the highest authorities in compa- 

 rative anatomy, and generally believed, that the animals be- 

 longing to the genus Rana, and indeed all the animals included 

 in the natural order ' Batraciens' of M. Cuvier, have a single 

 heart like fishes, composed of one auricle only and one ventricle. 



Many observations which I have made on the common toad, 

 have led me to a different conclusion, and have satisfied me to 

 demonstration that the heart of this animal has two auricles. 



This structure is displayed without much difficulty by minute 

 dissection. It is best exhibited by making a transverse incision 

 into the ventricle, close to its base, and inflating the cavities with 

 the blowpipe. In this way, and using fine probes, it may be 



