CORRESP ONDENCE. 



743 



CORRESPONDENCE. 



THE GERM THEORY. 



To the Editor of the Popular Science Monthly. 



IN your February number, Dr. J. R. Black 

 assumes to correct Dr. Niemeyer's 

 statement that the night-air of large cities 

 is less noxious than the stirred-up air of the 

 daytime, and he does so with a degree of 

 confidence that seems to imply that there 

 can be no such thing as doubting that he 

 speaks ex cathedra. 



Now, Dr. Black evidently believes that 

 the insalubrity of city air depends upon the 

 amount of non-respirable gases that may 

 be diffused into the respirable ones ; and 

 is wholly independent of the condensible 

 effluvia of the vaporous kind, or of the 

 organic germ-dust that the heat and stir of 

 the day may keep suspended, but would 

 settle with the cooling and quiet of the 

 night. 



Now, while the precise application of the 

 law to cities has not been made before, per- 

 haps, in your journal, the teaching which in- 

 evitably leads to it has been abundant, and 

 from unquestionable authority, so that, if 

 Dr. Black wishes to correct so fatal an error 

 as he charges this to be, he is very late with 

 his solicitude. One lecture of Tyndall's, 

 published by you, devoted much detail to 

 the experiments of the professor, in his at- 

 tempts to bottle a sterilized infusion in the 

 laboratory of the Royal Institution, in air he 

 had attempted to sterilize there, and ex- 

 plaining that he did succeed in a special 

 chamber elsewhere. If, as Dr. Black would 

 imply, noxious effluvia obey the law of diffu- 

 sion of permanent gases, how comes it that 

 they specially hover over low marshes and 

 putrefying cesspools, while the ascent of a 

 mountain of considerable elevation carries 

 us above malaria and aerial infection, and 

 often above bacterial decay ? 



A recent experiment of Tyndall's was 

 to sterilize a bottle of infusion and open it 

 upon the brink of a precipice, and, after 

 contact with the air, recork it, to observe 

 whether the infusion retained its sterility or 

 not. He found the air germless. The ex- 

 periment was made to test this identical 

 question of the settling of ferment-germs. 



Pasteur tried similar experiments, as- 

 cending to high points in Paris, bottling and 

 comparing the air so bottled in putrefactive 

 power with air bottled upon Mont Blanc, 

 and with the air of the streets of Paris, al- 

 ways with the result of finding the air of the 

 street levels more laden with micronymes 

 than that obtained at considerable eleva- 



tions. Upon the Western Plains, before 

 civilization had scattered its filth, laden 

 with zymogens, meats hung up in the air, 

 even in midsummer, would keep sweet for 

 days. The emigrants of 1849, in crossing the 

 Plains, were surprised to find often the car- 

 casses of dead animals of a previous caravan, 

 drying-up viscera, and all without decay. 

 This is easily explained on the germ-theory ; 

 without, it is inexplicable. If Dr. Black has 

 any evidence that the germ-theory of decay 

 and zymotic diseases is untenable, he should 

 presently submit it, for, to my thinking, the 

 world is only waiting to hear from Dr. 

 Charlton Bastian, when the testimony and 

 argument will be declared closed. 

 Respectfully, 



C. W. Johnson. 

 Atchison, Kansas, February 20, 1S78. 



THE HORSE IN AMERICA. 



We extract the following from a private 

 letter of a Swiss archaeologist : 



" In The Popular Science Monthly of 

 last November, page 121, I read that in 

 Colorado on ruins more than 500 years old, 

 probably much older, there are found draw- 

 ings of horses. Can this be correct ? I 

 know there are found fossil remains of 

 horses in America, but I know also that 

 the horse was totally extinct in America at 

 the time of its discovery by the Spaniards. 

 Ruins on which drawings of horses are 

 found must, therefore, be more recent than 

 the discovery of America by the Spaniards. 

 The well-preserved cedar-wood indicates 

 that the ruins cannot be as old as the fossil 

 horse. From the fact that no signs of a 

 door are visible in the outer walls, and the 

 ingress was from the top, I conclude that 

 these ruins must have been built by the 

 Pueblo Indians, or an allied race. I be- 

 lieve the Pueblo Indians to be the last re- 

 mains of a more highly-civilized race, per- 

 haps identical with the mound-builders, and 

 would attribute to the same race the anti- 

 quities of Arizona. They have been almost 

 exterminated by the later invasions of very 

 distinct tribes. The aborigines of America 

 did not know in 1492 the use of iron. That 

 a skeleton in a Utah mound (page 123, 

 ibid.) would have been found with a huge 

 iron weapon in the right hand is therefore, 

 for me, quite incredible. Also the occur- 

 rence of wheat in the same mound and of 

 bones of sheep in the Colorado ruins. Except 



