48 TUBERCULOSIS 



on the tongue. Demme reports four childdren who were infected by 

 a nurse who was accustomed to put the spoonful of food to her lips 

 and tongue in order to test its temperature in feeding the children and 

 I have seen a mother chew the food given her children. The esoph- 

 agus and stomach are seldom or never the sites of tuberculous 

 lesions. The food quickly passes the esophagus and the acidity of 

 the stomach contents protects that organ. In most cases of infection 

 by way of the alimentary tract the bacilli find lodgment in the small 

 intestine, through the walls of which they may pass without leaving a 

 recognizable lesion. 



There are three forms of tuberculous skin affection, tuberculosis 

 verrucosa, lupus and tuberculous ulcer. These may be due to scratch- 

 ing with infected finger nails, cuts with infected knives or wounds 

 with other infected instruments. Tuberculosis of the skin is especially 

 frequent among butchers. A general infection may result through 

 the skin. Several cases of infection through the rite of circumcision 

 have been reported and medical students have been infected in dissect- 

 ing tuberculous bodies and surgeons in doing operations and making 

 postmortems. In all these instances the infection extends to the near- 

 est lymph glands and then on to the next. The point of entry may or 

 may not show a lesion. Infection of the joints and bones is always 

 secondary. 



Sources of Infection. The most abundant source of infection is 

 dried tuberculous sputum. So long as the sputum is moist it is not 

 distributed through the air. When deposited on sidewalks, the sputum 

 adheres to the feet or may cling to the clothing and in either case 

 is carried into the house where it becomes more dangerous. The 

 greatest danger is in closed rooms in which sputum has been deposited 

 on the floor. Cornet made the following experiment which illustrates 

 how infection may be spread. A carpet which had been contaminated 

 with infected sputum some days before was spread on a floor. Cages 

 containing 48 guinea-pigs were placed at different levels in the room 

 and the carpet was vigorously swept with a broom until the room was 

 filled with a cloud of dust. Of the guinea-pigs exposed to this dust, 

 all but one became tuberculous. The same investigator sponged the 

 walls of a room occupied by a tuberculous patient who expectorated 



