This is in some Degree a _Coagulation_ of the Blood, which will the more certainly, when attended with an extraordinary Heat, as in the present Case, produce such like Effects as these, because the _Spirits_ separated from the Blood thus Inflamed, and Compounded of hard, fixt and dry Particles, must unavoidably share in this Alteration; that is, whereas their Fluid consists of two Parts, _One_ more active and Volatile, the _Other_ more Viscid and Glutinous, which is a kind of Vehicle to the former; their _Active_ Part will bear too great a Proportion to the _Viscid_; and thus they must necessarily be of more than ordinary Volatility and Force, and will therefore, upon the least Occasion imaginable, be irregularly determin’d to every Part; and hereupon will follow Tremblings of the Body, Anger or Fear upon a light or no Cause, extream Pleasure at what is but a Trivial Entertainment, as Red, Green Colours, or the like; and on the other hand, wonderful Sadness at any thing not agreeable to the Eyes, as dark and black Things; nay, ridiculous Laughter, obscene Talk and Actions, and such like Symptoms; because in this Constitution of the Nervous Fluid, the most light Occasion will make as real a _Reflux_ and _Undulation_ of it to the Brain; that is, will present as lively and vivid _Species_ there, as the strongest Cause and Impression can produce in its natural State and Condition; nay, in such a Confusion, the Spirits cannot but sometimes, without any manifest Cause at all, be hurried towards those Organs, to which at other times they have been most frequently determined; and every one knows which they are in hot Countries and Constitutions. We must however here remember what in the former Essay we mention’d of the Fluid of the Nerves, being _immediately_ altered by the venomous Juice. It will perhaps make this Theory more than probable, to consider that _Baglivi_ (53), in the Dissection of a _Rabbit_ kill’d by a _Tarantula_, found the Blood Vessels of the Brain very turgid, and the Substance of the Brain it self, that is, the Beginning of the Nerves, lightly inflamed, and with livid Spots here and there, the _Lungs_ and other _Viscera_ distended, with concrete glotted Blood, and large Grumes of Blood with _Polypous_ Branches in the Heart, a large Quantity of extravasated _Serum_ upon the Brain, which is (as he takes Notice) mostly observed in those Subjects which died by a Coagulation of the Blood. Neither is it amiss to remark, that in a _Chlorosis_ there is nothing preternatural but an _infarctus_ of the Arteries, and hence a retarded _Circulation_, from an Evacuation suppress’d; and in this Country too much Heat; that is, a beginning _Coagulation_, together with an Inflammatory Disposition. In short, _Bellini_ has at large demonstrated, how _Deliria_, as well as _Melancholic_ as _Manaical_, do proceed from a State of the Blood and Spirits, not unlike to that I have here described.