128 SCIENCE REMAKING THE WORLD 



may occur daily in our crowded cities. Nurses, 

 physicians, or employees in hospitals and sanatoria for 

 tuberculosis are not thought to be in any considerable 

 danger. In the latter case the patients are trained in 

 the employment of sanitary precautions and tubercu- 

 losis is more rare in this class of hospital employees than 

 in the same class outside of institutions. Consequently 

 the presence of such an institution in a community is 

 of no danger to its population. Milk from cows not 

 proven to be free from tuberculosis is undoubtedly a 

 source of danger, especially to young children whose 

 intestinal wall will not always prevent the tubercle 

 bacillus from entering the lymphatic system. Proper 

 methods of pasteurization remove this danger. 



SYMPTOMS OF PULMONARY TUBERCULOSIS. The 

 symptoms of pulmonary tuberculosis at the onset are 

 cough with or without expectoration, loss of weight and 

 strength, slight rise of temperature, and the spitting 

 of blood. Any one or any group of these symptoms 

 should arouse suspicion, and the patient merits a phys- 

 ical examination and an examination of the sputum, 

 if there is any, for tubercle bacilli. If they are present 

 it is a positive diagnosis. The examinations should be 

 repeated if symptoms persist and an X-ray examination 

 should be made also. The disease may be active, how- 

 ever, and detected by medical examination even when 

 no symptoms exist. Fortunately this condition is re- 

 latively rare. Persistent cough and unexplained fever 

 are danger signals and a pulmonary hemorrhage or 

 hemoptysis is almost positively diagnostic. If the 

 disease progresses, cough and expectoration, fever, 



