1885.] Anthropology. 105 
communal towns perched upon the mesas of Northeastern Ari- 
zona, and relates with great minuteness his attendance upon the 
snake dance, a rite which seemed revolting even to the enthusi- 
astic narrator. Everybody should read the book. We do not 
know which to praise the most, the author for shaking off the 
lethargy of camp life and gathering the material, the happy, often 
frolicksome style in which the work is written, or the beautiful 
illustrations which throw so much light upon the text. We have 
only space here to say that in the month of August every year 
the Moki celebrate a snake dance. Eight days before the dance 
the young men go north one day, west one day, south one day, 
east one day, and the other four days they roam all over the 
country, if necessary, to catch the snakes, using all kinds. These 
reptiles are placed in an estufa until wanted, kept in order by 
certain old men who have no other weapon except a small stick, 
at the end of which are two eagle feathers. The snakes are afraid 
of the birds of prey, and seem to have a wholesome dread even of 
their feathers. After the most elaborate preparation, witnessed 
by Captain Bourke, the dancers march through the principal 
streets, certain of them carrying each a squirming snake in his 
mouth, the animal being kept in order by a companion using the 
eagle-quill teaser. The closing chapters of Captain Bourke’s 
volume are devoted to the daily life and customs of the seven 
Moki towns. 
Way TroricaL Man 1s Bracx.—Dr. Nathaniel Alcock con- 
tributes to Wature a very interesting paper in which he argues 
that light and actinism have codperated with heat in the coloring 
of the skin. If man could live by heat alone, in the tropics the 
black man would be fittest, because he would be the hottest. But 
light has also played such an important part that those in whom 
a portion of the rays of the glaring sun are blocked at the sur- 
face are best adapted for survival beneath its vertical beams. The 
waves of light and heat follow each other at similar rates through 
the luminiferous ether. When light or heat impinges on man its 
_ waves select those atoms whose periods of vibration synchro- 
nize with their own period of recurrence, and to such atoms de- 
liver up their motion. It is thus that light and radiant heat are 
absorbed. Heat waves thus notify their existence along the sur- 
face fiber to the central nerve cell, and so enable the animal to 
avoid their action, if excessive, or seek their increase if deficient. 
While heat waves are thus received and responded to, their fel- 
low workers, the waves of light, are not inert. 
Admitting that theoptic nerves are but nerves of the skin, 
whose molecules once could vibrate only with the large ultra-red 
waves of heat, it must be conceded that in the first instance all 
surface nerves must have felt the influence of that agent by which 
they are to be hereafter exalted. But a yet more wondrous les- 
son is to be learned from the steps which nature takes for the 
