156 



SCIENCE. 



[Vol. XX. No. 502 



paths has come to know as groundless. The puma, or American 

 panther, and its South American representative, the jaguar, are 

 not regarded by experienced hunters and naturalists as animals to 

 be feared, excepting under circumstances which leave no avenue of 

 escape open to the beast. The writer has repeatedly observed this 

 fact in connection with the puma in this country, with the jaguar 

 in the forests of the Amazon, and with various other wild ani- 

 mals, in both regions, wliich are terrible antagonists when brought 

 to bay by wounds or other events demanding defence of self or 

 young. The puma plays like a cat about the lonely traveller on 

 foot or pnow-shoes in the Rocky Mountains, and the curiosity of 

 the jaguar brings him nightly to the camps of voyagers along the 

 Brazilian rivers. I have often in that region been disturbed in 

 sleep by such prowlers, who would rush suddenly off upon the 

 slightest movement of my body; and upon numerous occasions in 

 the morning fresh tracks in the sand all around our blankets 

 would be visible, many times without our being awakened by the 

 movements of the animals. 



Mr. Hudson's remarks regarding the fearlessness of the natives 

 in La Plata do not, however, agree with my own observations of 

 the average Amazonian dwellers. As an instance, one night in 

 1870, at the Cachociras (waterfalls) de Maroim upon the Tocantins 

 River, some 200 miles above the city of Para, we encamped in 

 the forest at the edge of the river, contrary to our usual custom 

 of selecting a sandy island. Some in hammocks, others with 

 blankets spread upon the ground, we North-Americans all slept 

 soundly, notwithstanding that a rock cavern with well-gnawed 

 bones and other signs of jaguar occupancy lay within 300 feet of 

 the camp. I did awake once and saw the glaring eyes of a huge 

 jaguar, as I supposed, within a few feet of my hammock. Next 

 morning the tracks were evident in this particular spot, as well 

 as many others all around camp, which were not there when we 

 lay down at night. But the natives ! Every mother's son of 

 them uttered that night fervent prayers for pi-otection, and sought 

 rest in the tree-tops, swinging their hammocks from limbs hang- 

 ing far out over the water, at the same time cautioning us of the 

 great danger to be feared from vicious attacks of the tigers. This 

 is only one of a number of similar instances, and not a little ex- 

 perience with the puma and with bears of various kinds (including 

 the cinnamon and grizzly) and other animals of reputation for 

 unbridled ferocity, has brought me to the same conclusion regard- 

 ing them. The writer called attention to the harmless nature of 

 some supposed dangerous feres as early as 1873-74 in articles in 

 the American Naturalist upon " The Scientific Value of the Yel- 

 lowstone Park." 



Venomous reptiles and insects, as the rattlesnake, " Gila Mon- 

 ster," tarantula, scorpion, centipede, etc., have reputations beyond 

 their deserts for blood-thirstiness. Notwithstanding the numer- 

 ous authentic cases of poisoning by them, I have yet to learn of 

 one which cannot be fairly regarded as the derrier resort of the 

 animal in a defensive attitude. Give any one of these creatures 

 a reasonable (to their notion) chance of escape and they will avail 

 themselves of it in preference to attack. One may come upon 

 them suddenly, and unconsciously put them in a position from 

 which no escape is open; but, if they are let alone or given a free 

 field, they will always avail themselves of it. I remember the 

 case of a rattlesnake in Texas, which we had surrounded and 

 which was menaced by clubs upon all sides. He ran for dear life, 

 striving his best to pass the gaps between each pair of enemies, 

 until, baffled at every point, he suddenly turned upon the writer 

 for an attack. As soon, however, as this manoeuvre had opened 

 a passage-way in one direction, he darted off and was again 

 caught only with great difficulty. So, in Indian Territory, among 

 the Wichita Mountains, where the rattlesnakes are akin to boas 

 in size and hideousness, they are wofully sluggish. I have en- 

 countered them there among the rocks and in the tall grass, with 

 the sickening rattle sounding long enough to get far from harm be- 

 fore the dangerous thrust was made. My horse has almost stepped 

 upon them in such situations in that region, as well as in Wyoming, 

 Texas, Arizona, and elsewhere, without further result than a 

 scampering off of the snake. Much as the boa constrictor is 

 dreaded in Brazil, cases are exceedingly rare of the exercise of its 

 undoubted power over humanity. 



The alligator, with all his ability to devour, is an arrant coward, 

 and we often bathed in the tropical rivers where they were dis- 

 porting themselves not far away. The natives there claim that 

 none but drunken men are in danger from their attacks. 



Hunger, endangerment of life, excessive fear of man with no 

 means of escape, and a sudden surprise are all effective in bring- 

 ing up every means of defence. The real danger from association 

 with many of these creatures is the liability to meet them una- 

 wares, or to suddenly place them on the defensive through the 

 unconscious movements of sleep. The more sluggish or the smaller 

 the animal, the greater is this risk. 



In Arizona the bite of a certain small species of skunk is very 

 much dreaded, owing to the belief that hydrophobia is a probable 

 result. There is almost no danger from this source, nor from the 

 vile excretions of other species of polecat, if one does not directly 

 attack them ; but from their unfortunate sociability in this region, 

 a sleeping person may suddenly throw out his hand when dis- 

 turbed, without awakening. In nine cases out of ten this will 

 drive off the intruder, who will rarely return. Occasionally, 

 however, such an act may hit the animal, when he will bite as he 

 flees. Very few cases of this kind have been reported. I have 

 frequently discovered innumerable tracks of these animals about 

 my cot of a morning when camping in sandy tracts, and some- 

 times have seen them moving about, A movement of the arm is 

 always enough to send them post-haste to cover at a distance. 

 Persons lying on blankets on the ground need more caution, as 

 these "essence peddlers " will sometimes occupy such beds on cold 

 nights. 



Skunks are extremely abundant for several weeks in autumn in 

 this region. Last year four of them entered the university itself, 

 and at one point in the Baboquivon Mountains as many as thirty 

 were killed near our cabin in two or three days. They would 

 come up to the doors at midday, and as many as seven at one 

 time were seen on moonlight nights within shooting distance. 



These pests have again made their appearance this month. 

 There seem to be four kinds of them, varying materially in 

 " scentability " from the inodorous little biter to the one which is 

 the very quintessence of malodorousness, and m color from a light 

 gray to a dense black with white tail. Somehow or other, one of 

 each kind inhabited a cosy nook beneath the writer's office last 

 fall. The little gray one was particularly fond of intruding into 

 my bed-room until the shot-gun was called into requisition. 



Tucson, Arizona, Sept. 5. 



CONCERNING THE AERATION OF MILK. 



BY 0. S. PLUMB, DIRECTOR A(3RICULTURA.L EXPERIMENT STATION OF 

 INDIANA. 



Much advance has been made in our knowledge of dairying of 

 late years, and especially in America has there been much atten- 

 tion devoted to problems affecting the industry, which has resulted 

 in remarkable progress. Some of the American agricultural ex- 

 periment stations have made themselves be^t known by the dairy 

 investigations they have conducted. 



Among these subjects of study has been that of the influence 

 of aeration upon milk. Milk fresh from the cow, that was aerated 

 and suddenly reduced in temperature at the same time, it was 

 claimed, would remain sweet longer than milk not so treated 

 set under similar conditions. Within a comparatively short 

 time aerating machines have been placed on the market, that are 

 credited with removing disagreeable odors and retarding acidity 

 of milk. 



Bulletin 27 of the Vermont Experiment Station, for January, 

 1893, states that the "aerator gave good satisfaction" when in 

 use at that institution. At the Cornell University Experiment 

 Station the aeration and cooling of milk were studied by Professor 

 H. H. Wing, and the results published in Bulletin 39, for July, 

 1892. In this it is shown that the Champion aerator will cool 235 

 to 350 pounds of milk per hour down to about 60" F. Milk passed 

 over the Champion was, on an average, perceptibly sour in fifty 

 hours after setting; that aerated on the Star machine was sour in 

 fifty-one hours; while milk aerated with the Powell machine 



