1869.] On the Action of Hydrochloric Acid on Morphia. 455 



existing species it characterizes the Camelidce, occurring also, as shown 

 in Palauchenia, in the fossil form of that family ; but this rare disposition 

 of the vertebral arteries was likewise met with in a large fossil Ungu- 

 late of South America, Macrauchenia, belonging to the Perissodactyle 

 group*. 



The author therefore communicates, as an appendix to his former paper 

 on Palauchenia, a description, with drawings, of the mandibular dentition 

 of Macrauchenia patacho?iicha, of the natural size, the lower jaw of that 

 fossil animal being still a unique specimen in the British Museum. It 

 displays the entire molar series, with the exception of the first small pre- 

 molar : the several teeth in place are described in detail and compared with 

 those of other Perissodactyles. The grinding-surface of the true molars 

 presents the bilobed or bicrescentic type, as in Palceotherium and Rhino- 

 ceros ; but Macrauchenia differs from both those genera in the limitation 

 of the assumption of the molar type to the last premolar, the antecedent 

 ones retaining the single-lobed crown, From Palceotherium it further dif- 

 fers in the last molar being bilobed, as in Rhinoceros, not trilobed. In 

 Palauchenia all the premolars have the simpler structure, as in Artiodac- 

 tyles generally. Macrauchenia resembles Anoplotherium and Dichodon 

 in retaining the typical dentition, c J^J, ^jEj, m ^E^ = 44, and in 



the uninterrupted course of the dental series, not any of the teeth having 

 a crown much higher or longer than the rest. 



The paper is illustrated by drawings. 



III. " Researches into the Chemical Constitution of the Opium 

 Bases. Part I. — On the Action of Hydrochloric Acid on Mor- 

 phia." By Augustus Matthiessen, F.R.S., Lecturer on 

 Chemistry in St. Bartholomew's Hospital, and C. B. A. Wright, 

 B.Sc. Beceived May 6, 1869. 



It has been shown that when narcotine is heated with an excess of con- 

 centrated hydrochloric or hydriodic acid, one, two, or three molecules of 

 methyl are successively eliminated, and a series of new bases homologous 

 with narcotine obtained. It appeared interesting to see if any similar re- 

 actions took place with morphia ; and for this purpose a quantity of that 

 base, in a perfectly pure state, kindly furnished by Messrs. M'Farlane, of 

 Edinburgh, was submitted to experiment. The purity of the substance 

 was shown by the following analysis. 



It was found that although crystallized morphia does not lose its water 

 of crystallization in an ordinary steam drying-closet (i. e. slightly below 

 100°), yet it readily loses the whole when placed in a Liebig's drying- tube 

 immersed in boiling water, dry air being aspirated over it. 



* Odontography, 1846, p. 602. 



