29 



perception of these explosions ; and lastly, that the hearing will be 

 strongly affected by introducing into the ears two probes, the oppo- 

 site extremities of which are connected with the two ends of the ap- 

 paratus. No effect has as yet been produced upon the sense of smell 

 by this machine, which is ascribed to the circumstance of the electric 

 effluvia not being expanded in and conveyed by the air, which it is 

 thought is the proper vehicle for exciting sensations in the olfactory 

 nerves. 



At the close of the paper the author points out the striking analogy 

 there is between this apparatus and the electric organs of the tor- 

 pedo and electric eel, which are known to consist of membranaceous 

 columns filled from one end to the other with a great number of la- 

 minae or pellicles, floating in some liquid which flows into and fills 

 the cavity. These laminae cannot be supposed to be excited by fric- 

 tion, nor are they likely to be of an insulating nature ; and hence 

 these organs cannot be compared either to the Leyden phial, the 

 electrophore, the condenser, or any other machine capable of being 

 excited by friction. As yet, therefore, they can only be said to bear 

 a resemblance to the apparatus described in this paper. The effects 

 hitherto known of this apparatus, and those which there is every 

 reason to expect will be discovered hereafter, are likely, it is thought, 

 to open a vast field for reflections and inquiries, not only curious but 

 also interesting, particularly to the anatomist, the physiologist, and 

 the physician. 



Some Observations on the Head of the Ornithorhynchus paradoxus. 

 By Everard Home, Esq. F.R.S. Read July 3, 1800. {Phil. 

 Trans. 1800, p. 432.] 



We learn from this communication that the beak of this singular 

 animal, which on a cursory examination was thought to be exactly 

 similar to that of the Duck, and calculated for the same purposes, is 

 in fact materially different from it ; and that, so far from being the 

 mouth of the animal, as had been imagined, it is only a part added 

 to the mouth, and projecting beyond it. This mouth has two grind- 

 ing teeth on each side, both in the upper and lower jaw ; they are 

 without fangs, and may be considered as bony protuberances. In- 

 stead of incisor teeth, the nasal and palate bones are continued for- 

 wards, so as to support the upper portion of the beak ; while the two 

 under jaws are likewise continued forwards in the shape of two thin 

 plates of bone, forming the central part of the under portion of the 

 beak. The tongue is very short, and when extended can be projected 

 into the bill scarcely one quarter of its length. 



The organ of smell in this animal differs from that of quadrupeds 

 in general, as well as of birds. The nostrils are nearly at the end of 

 the beak, while the turbinated bones are situated in the skull, as in 

 other quadrupeds ; by which means there are two cavities the whole 

 length of the beak superadded to this organ. The nerves which sup- 

 ply this organ are very large in proportion to the size of the animal. 



