It was with melancholy amusement that I read in the scientific journals that sewer-gas was comparatively innocuous. After the hundreds of sanitary tracts in which the deadliness of sewer-gas has been an axiom of faith, after the thousand-and-one deaths from it in the contemporary novel, it is grimly diverting to learn that sewer-gas may be welcomed without fear to our hearths and homes. The same process appears to be overtaking science with which we are familiar in the sphere of history--all the bad gases are getting purified and the good spirits vilified. The invincible solids are being liquefied, and the aëry nothings are being given solid habitations. The Professor tells me that liquid oxygen is obtainable only under great pressure, and at a colossal cost. I beg respectfully to suggest to the millionaires the advisability of laying in quarts of it for their dinner-parties. This sparkling beverage--essence of oxygen, mark you--would not need to be iced, for the North Pole is as a red-hot poker compared with it. Such a beverage would make a sensation and provide paragraphs for the society journals and the "Times" obituary. It is true the guests would not like it, but they would be anxious to quaff it. Have you never noticed the innocent joy which the pop and froth of cheap champagne gives to suburban souls? There is a magic halo about champagne--an aroma of aristocracy--which sanctifies it for people who would be happier with lemonade. Wherefore I doubt not there would be a public to adventure on liquid oxygen, though it were congealed in the attempt. The imbibition thereof might indeed replace suicide and cremation--it would both kill and cure, and our frozen bodies might be preserved in family ice-safes for the edification of scientific posterity. I should not marvel if liquid air or oxygen became an article of the euthanasian creed. As for sewer-gas, we may yet live to see it manufactured artificially for the improvement of the public health, and conveyed to our overcrowded drawing-rooms with all the paraphernalia of pipes and the mendacious meter. Science has turned so many somersaults even in my short lifetime that I am prepared for anything. I have even serious doubts as to the stability of Darwinism, I have seen so many immortal truths die young. I verily believe that the cocksureness of our century is destined to be the amusement of the next, which may not impossibly believe that the ape is descended from man by retrogression. Our little systems have their day, They have their day--and come again.