MAN AND THE MICROBE 17 



The danger of contact infection from such gross discharges as the 

 sputum are sufficiently obvious. Material of quite as dangerous a 

 nature is thrown out from the mouth a3 a fine spray in coughing, 

 sneezing or loud speaking. Furthermore, it is a sad fact that cleanli- 

 ness in a bacteriological sense is a very rare thing and the hands are 

 usually more or less soiled with discharges from the nose and throat 

 and too often from the intestines as well. Br. C. V. Chapin, in his 

 classic book, on " The Sources and Modes of Infection," has some strik- 

 ing paragraphs which, though not pleasant reading, must be pondered 

 by all who would really understand how communicable disease is spread. 



Probably the chief vehicle for the conveyance of nasal and oral secretions 

 from one to another is the fingers. If one takes the trouble to watch for a short 

 time his neighbors, or even himself, unless he has been particularly trained in 

 such matters, he will be surprised to note the number of times that the fingers 

 go to the mouth and the nose. Not only is the saliva made use of for a great 

 variety of purposes, and numberless articles are for one reason or another placed 

 in the mouth, but for no reason whatever, and all unconsciously, the fingers are 

 with great frequency raised to the lips or the nose. Who can doubt that if 

 the salivary glands secreted indigo the fingers would continually be stained a 

 deep blue, and who can doubt that if the nasal and oral secretions contain the 

 germs of disease these germs will be almost as constantly found upon the fingers? 

 All successful commerce is reciprocal, and in this universal trade in human 

 saliva the fingers not only bring foreign secretions to the mouth of their owner, 

 but there exchanging them for his own, distribute the latter to everything that 

 the hand touches. This happens not once but scores and hundreds of times dur- 

 ing the day 's round of the individual. The cook spreads his saliva on the muffins 

 and rolls, the waitress infects the glasses and spoons, the moistened fingers of 

 the peddler arrange his fruit, the thumb of the milkman is in his measure, the 

 reader moistens the pages of his book, the conductor his transfer tickets, the 

 "lady" the fingers of her glove. Every one is busily engaged in this distribu- 

 tion of saliva, so that the end of each day finds this secretion freely distributed 

 on the doors, window sills, furniture and playthings in the home, the straps of 

 trolley cars, the rails and counter and desks of shops and public buildings, and 

 indeed upon everything that the hands of man touch. What avails it if the 

 pathogens do die quickly? A fresh supply is furnished each day. 



The control of contact transmission, the breaking of the chain of 

 communication between the infected and the non-infected person, in- 

 volves one or both of two measures. On the one hand, the spread of 

 infective material from sick persons and carriers must be checked, so 

 far as possible, and, on the other hand, the mouths of well persons must 

 be guarded against infective material which, despite all our efforts, will 

 to some extent be distributed in the world about us. The first half of 

 this task involves the recognition of the sources of danger, and is of 

 course greatly complicated by the presence of the unrecognized carriers. 

 Much may be hoped, however, from the development of what may be 

 called the sanitary conscience, the recognition on the part of each man, 

 woman and child of the grave responsibility which he may incur by 



vol. lxxxv. — 2. 



