Volume 1

The works of John Hunter / edited by James F. Palmer.

Date:
1835-37
Catalogue details

Licence: Public Domain Mark

Credit: The works of John Hunter / edited by James F. Palmer. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    causes and effects of this matter, have, from a poverty of language, ap- plied the word which was at first only expressive of a quality to the thing itself, so that by heat now is also meant the matter of heat abstracted from the sensation which it occasions* * * §. This is so much the case, that Dr. Blackf makes use of the term latent heat to signify that heat which a body contains without imparting it to the senses, as we might call the water which goes into the formation of salt latent water; in other words, that water which the salt contains without losing its solidity. It has been much disputed whether heat is matter, or only a property of matter. If it is simply matter, then wherever there is heat there must be that matter present. If heat is a property of matter, there must be both matter and property present. If heat is only an action in a particular matter, then there is that matter with its action, as also the body which throws this matter into the action+. Heat and cold are opposite principles, and cannot inhabit the same place §. They occupy different parts of the globe, and in some places alternately; these, therefore, are subject to the variations of temperature, which cause varieties of climate. These will be further spoken of hereafter. Heat, although not equally distributed all over the globe, yet exists in such a degree as to pervade all matter, and is therefore to be found in some proportion everywhere. Heat destroys attractions of all kinds, by which means it becomes the principle of fluidity, and consequently * [The sense of this inconvenience has given rise to the general use of the term caloric for the agent which produces the sensation of heat.] f [In connexion with the name of Dr. Black, we may mention that it was not until this able philosopher had completed his train of researches on the subject of heat that the true theory of respiration began to be understood, or the connexion which sub- sisted between this function and the production of animal heat. Previous to this time the lungs were considered merely as the agent for cooling the blood.] + [Whether heat consists of a highly attenuated subtle matter which pervades all things, or of a vibration among the atoms of matter, has not yet been decided. Its leading feature is evinced in the repulsion which it produces among the particles of matter, in which respect it is the proper antagonizing force to attraction. Whatever it is we do not know anything of the principle itself, or of the manner in which it produces its effects. The subject of animal heat occupied a great deal of Mr. Hunter’s attention, in con- sequence of which he made it the subject of two express papers in the Philosophical Transactions, besides recurring to it again very fully in the Treatises on Inflammation and the Animal (Economy. The reader is referred to these works in the third and fourth volumes for fuller information.] § [Cold was formerly thought by philosophers to be a positive principle, like heat, instead of a mere negation or absence of heat, as it is at present almost, if not quite, universally considered. It is in the former view that Mr. Hunter speaks of it.]