Smell. 475 



The sensation of smell is strongest when the irritation is freshest, and 

 it is assisted by "sniffing." Our sensibility in all sensory irritation is 

 more acute when the irritation is sudden, either in beginning or ending. 

 A sound like the hum of a mill when first begun will arouse our atten- 

 tion, but if continued monotonously will make us drowsy. So of smell ; 

 the first irritation awaking attention, while a continuation of it obscures 

 it. And its revival requires the sudden renewal of sniffing. 



Smell is the most delicate of all the senses ; and we can by it gain a 

 knowledge of substances that we cannot begin to see, taste or touch. 

 "We can smell three one hundred millionths ( 100 O Q O 000 ) of a grain of 

 musk. No chemical reaction, nor even spectrum analysis, can detect 

 what we can smell, and yet the spectrum can recognize t 000 of a 

 grain. 



The odor of rosemary is perceived at sea off the coast of Spain before 

 the shore is in sight. A grain of musk will scent a room a year. Haller 

 kept papers scented 32 years with one grain of amber each square inch 

 of surface of paper was impregnated with 2 69 *64 ooo P art of a g rain 

 and perfumed besides a stratum of air one foot deep, for 11,600 days or 

 about 32 years. ( Papillon. ) 



The delicacy of smell even in our race is often very refined. A cer- 

 tain woman foretold storms several hours in advance by the sulphurous 

 odor, probably due to ozone in the air. A deaf mute is on record as be- 

 ing able to distinguish various plants by the odor alone. But many of 

 the lower animals are far ahead of us in the delicacy of this sense. A 

 hound can smell an animal entirely out of sight. Deer, Buffalo and other 

 game can scent the hunter, if on the windward side, quite beyond rifle 

 range. A dog can follow his master and pick out his particular odor in 

 a crowd of men, and he can follow any animal by the odors clinging to 

 its tracks hours after they are made. Beavers and many other animals 

 possess similar faculties. The Lemur possesses an excellent smelling 

 organ. Birds of prey can often smell further than they can see. Crows 

 will scent a carrion at the distance of a league. Reptiles and fishes have 

 large olfactor}" lobes, but since the vehicle of odorous particles in this 

 case is water, and come in solution instead of a gas, the sense with them 

 must be somewhat akin to our sense of taste. 



We can readily see that our own smell organs would behave very dif- 

 ferently, perhaps be entirely subverted if immersed continuously in 

 water, while our taste organs would probably not be at all impaired. 

 The whale tribes, which are modified from land mammals, have to a great 

 extent lost the sense of smell. Porpoises have no olfactory nerves at 

 all and no turbinal bones. Walruses have small olfactories. 



Many essential oils of plants are agreeable in their odors, the reason 

 of which is not obvious. They are combined for use in cologne water, &c. 



