286 THE POPULAR SCIENCE MONTHLY 



contact infection or inhalation of infected dust from the air. The infec- 

 tion of the saliva may then enter the system through the tonsils or the 

 alimentary tract. 



The skin of man and animals is constantly infected with many 

 germs, some of which are responsible for boils and abscesses, erysipelas 

 and certain diseases caused by molds or mold spores and yeasts. Dust is 

 a factor of importance in carrying these disease germs to a place where 

 they can invade the epidermis and bring about results which may become 

 serious. The germs settle on the skin and await the first opportunity for 

 multiplying at the expense of the tissues. Cleanliness is a far-reaching 

 preventative and reduction of dust in the air promotes cleanliness. 



One of the greatest benefits which will result from the increased use 

 of horseless vehicles will be the disappearance of horses and horse stables 

 from cities. This may not appeal to lovers of horses, but sanitary and 

 preventive measures can not be carried out without sacrificing certain 

 emotions. The germs and spores of lockjaw are common inhabitants of 

 the intestinal tract of horses. Dust from dried horse manure may 

 become the immediate cause of this dreaded and fatal disease. The 

 spores of lockjaw germs are highly resistant and may live in the air and 

 carry infection for months. A small amount of atmospheric dust enter- 

 ing a casual wound may result in serious diseaster, since a considerable 

 portion of atmospheric dust is really dried horse manure. Another much 

 feared disease is glanders or farcy. Horses are especially susceptible to 

 this disease which causes a discharge from the nose, frequently looked 

 upon in the initial stages as a cold. Carelessness may result in contact 

 with this discharge which carries the virus and by means of abrasions 

 of the skin of the stableman, rider or veterinarian the infection may be 

 communicated. Glanders usually terminates fatally. Cases of this 

 nature are by no means scarce. Both lockjaw and glanders will become 

 less frequent with the disappearance of horses from our streets. 



In some states and municipalities war has been declared upon the fly. 

 There are at least two species of flies which interest us in this considera- 

 tion, namely the house fly and the stable fly. It has been recognized 

 that flies may carry disease germs and thus become important factors in 

 spreading infection, not to take into account the discomfort, caused by 

 flies, to man and animals. In The American Journal of Public Health 

 of December, 1913, is reprinted part of an article of the September num- 

 ber of the Department of Public Safety of Eochester, N". Y., giving some 

 interesting figures on manure production and its relation to the fly 

 problem. 



There are 15,000 horses in the city. The average output of each horse con- 

 sists of thirty pounds of manure and eight pints of urine per day. It means 

 that the 15,000 horses deposit on the streets and in the stables of Eochester over 

 82,000 tons of manure annually. The total manure output of the city would 



