of Edinburgh , Session 1885-86. 961 
7. The Temperature of Loch Lomond and Loch Katrine 
during Winter and Spring. By J. T. Morrison, B.Sc. 
Communicated by Dr J. Murray. 
8. Note on the Surface Temperature near a Tidal Bace. 
By the Same. 
9. Further Bemarks on Dew. By John Aitken, Esq. 
10. On the Objective Cause of Sensation. Part II.— Taste. 
By John B. Haycraft, M.B., B.Sc., &c., Professor of 
Physiology in the Mason Science College and the Queen’s 
College Medical School, Birmingham. 
Much knowledge has already been gained regarding the nature of 
light and sound, and much is known as to the functions of both the 
eye and the ear. Little, however, has been learnt concerning the 
production of smell and taste, which is not the intellectual property 
of every educated man. The views of Hobbes and Hartley have 
been during late years rendered more acceptable by the remarkable 
discovery that the end-organs of special senses are all built up on 
the same plan. Developed as they are on the same lines from 
simpler, practically identical, ectodermic cells, we are forced with 
Herbert Spencer to look for similarities in the agencies which 
develop them. In the case of sight and hearing, it is already known 
that the quality of the sensation produced depends upon the nature 
— rapidity, complexity — of the vibrating stimulus. The particles 
of a liquid, as well as particles dissolved in water, are in constant 
and characteristic vibration. It has been my endeavour to discover 
whether in the case of taste also it will not be possible to connect 
the quality of the sensation with the nature or character of the 
vibration of the sapid particle. 
In the first place, it may be well to determine whether or no 
there is any relationship between taste sensation and the gross 
molecular weight of a sapid particle. 
If we take the molecular weights of acid substances, we shall find 
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