THE MICROBES OF HUMAN DISEASES. 223 



is an attenuated form of small-pox. The same treat- 

 ment applies to both diseases. When the patient is 

 kept in the purifying chamber of a gas manufactory, 

 where there is a constant disengagement of acid 

 vapours, sulphuretted hydrogen, hydro-carbons, coal 

 tar, benzine, carbolic acid, etc., the microbes embedded 

 in the throat and lungs are attenuated. Sulphate of 

 calcium is a successful remedy in whooping-cough as 

 well as in croup. 



Children who have had whooping-cough, or who 

 are passing through the disease, rarely contract croup 

 even when it is epidemic, although catarrh, inflamma- 

 tion of the bronchial tubes, ulceration of the mouth, 

 and general debility, are all predisposing causes of 

 croup. The question therefore arises whether whoop- 

 ing-cough does not act as a sort of preventive vaccina- 

 tion which may serve as a protection against croup. 

 Further researches and observations should be made 

 in this direction, if that which we now indicate can 

 be established as a fact. 



XI. THE MICROBES OF PHTHISIS AND OF LEPROSY. 



These two microbes are so similar in form that it 

 is necessary to have recourse to chemical reagents and 

 to staining processes in order to distinguish them 

 clearly. Both assume the form of an 8, or of slender, 

 elongated rods, so minute that it is not surprising 



