392 THE POPULAR SCIENCE MONTHLY. 



health was restored. Growers of hyacinths have noticed a 

 marked effect on their blooming when they are put in glasses of 

 certain colors. 



This age is a jDeculiarly health-seeking one, and it does not 

 seek health, as the Greeks did, by early rising, temperance, open- 

 air exercise, and training ; but it asks how health can be pre- 

 served and promoted by the removal of external sources of dis- 

 ease, so that it may have freedom to infringe with comparative 

 impunity Nature's laws. External poisons are the most impor- 

 tant things to protect ourselves from, especially when we have 

 enfeebled our bodies, and these are mostly conveyed to us by 

 mephitic vapors and what the doctors call septic dust. We want 

 our houses and other buildings so constructed that they can be 

 freed outside from their palls of dust and soot by means of a fire- 

 engine or a sponge, and inside by the broom, the dusters, and the 

 flannels of the housemaid. 



Foul and poisonous air has scarcely any connection with dec- 

 oration, but, with one or two exceptions, is in relation with pure 

 science and its applications. The exceptions are when some of 

 the materials used for decoration have a pernicious chemical 

 action on the air, or parts of their substance readily come off and 

 poison us when we breathe, or when in contact with our skin. 

 The former is said to be the case when preparations of arsenic 

 and some other dyes and pigments are used and are not varnished. 

 The dust that is not septic consists of minute particles of raw or 

 cooked earth, stone, and metal, and the ill effect it may produce 

 can only be from irritation of the mucous surfaces, by clogging 

 fine vessels, or by getting into parts where it is not wanted. Par- 

 ticles of some metals, if numerous enough, may poison us, as fire- 

 gilders are poisoned by mercurial fumes. The septic dust consists 

 of particles of vegetable or animal fiber, sometimes laden with 

 the germs of disease, the pollen of flowers, by some of which hay 

 fever is said to be produced, the eggs of microscopic creatures, 

 and microscopic creatures themselves. Another source of poi- 

 soning is by animal and human exhalations. 



Anything that forms a dust-trap is as far as possible to be 

 avoided, particularly when these traps can only be partially 

 emptied at long intervals, for every breath of air dislodges some 

 of the lighter particles. The absorbents of the foul-smelling ex- 

 halations have also the property of imparting them to damp air, 

 by which we are poisoned or repoisoned. Consequently we want 

 to avoid as much as possible all woven and felted stuffs in our 

 houses, and to have all wood and paper protected by varnish. 



Few of us can expect to live in houses built of polished granite, 

 porphyry, and jasper, and adorned with precious stones, but we 

 may expect to live in those protected and embellished with enam- 



