Of particular note for the greatly expanded second edition published in 1826. That edition contained 150 pages compared to 72 pages in the first edition. The second edition also contained 13 plates derived from images collected by Jean Esquirol, but published more than a decade before Esquirol published related images.
"In making a collection for this purpose, I have great pleasure in acknowledging my obligations to my friend Dr Esquirol of Paris, for his liberal permission to avail myself of his extensive collection of busts and drawings illustrative of the subjects ; and also to Dr. Sutherland, and to Mr. Wastell to London, for the facility afforded in selecting examples of different varieties, from a very large number of insane" (p.126).
"In March 1818, Morison travelled to Paris to meet Jean Étienne-Dominique Esquirol at the Salpêtrière. They corresponded for many years, Morison visited him on a further five occasions, and Esquirol subsequently sent students over to him. Morison visited a variety of Paris hospitals and was impressed with the French example that work could serve both as occupation and punishment. He noted the use of bath treatment with water to the head. He explored the theory of phrenology: he attended a lecture by Franz Joseph Gall and met with Johann Spurzheim, who told him he did not follow Esquirol’s classification of insanity."
Digital facsimile of the 1825 edition from Google Books at this link. Digital facsimile of the 1826 edition from the Internet Archive at this link.