of Edinburgh, Session 1885-88. 
621 
4. On the probable Heats of Formation of Zinc-Copper 
Alloys. By A. P. Laurie, Esq. 
5. On the Mean Free Paths in a mixture of Two Systems of 
Spheres. By Professor Tait. 
6. On Two Shrunk Human Heads from South America. 
By Professor Duns, D.D. 
The Indians, to whom the preparation of these heads is traced, 
are scattered oyer a wide tract of country on the eastern side of the 
Andes. They are known under the general designation Macas, 
the name of the region they inhabit — a designation which includes 
the Jivaros, Pastazas, Mendes, Tumbas, and more than twenty other 
tribes. Early brought into contact with the first Spanish invaders, 
they suffered much at their hands. Many references to them occur 
in the history of the Spanish settlers. Their appearance, social 
habits, and superstitious practices have much prominence given to 
them in the recent literature of South American travel. At present 
I limit my remarks mainly to the specimens of “ shrunk ” or 
reduced heads now before us. They are from several points of view 
remarkable, and raise several questions of great ethnological interest, 
but trustworthy references to them are comparatively few. Indeed, 
the only sources of information worth mentioning are a communica- 
tion by Mr William Bollaert, F.B.G.S., to the Ethnological Society 
of London, 1860, and another, by Sir John Lubbock, to the 
Anthropological Institute of Great Britain in 1873. The former is 
entitled “On the Idol Human Head of the Jivaro Indians in 
Ecuador;” the latter, “Note on the Macas Indians.” In Mr 
Bollaert’s paper special attention is given to a specimen obtained by 
M. Jose Felix Barriero, of the Secretariat of the Provincial Govern- 
ment, Quito, and sent by him to Don B. de Silva Ferro, Chilian 
Consul, London. This specimen was placed in the Ecuador Court 
of the International Exhibition, 1862. Sir John Lubbock’s paper 
is devoted chiefly to a general description of the Macas Indians. 
The red specimen of shrunk head now exhibited was sent to my 
friend Dr H. Gunning of Palmeiros, Bio de Janeiro, a Fellow of 
