baffled the combined efforts of medical scientists. Its exis- 

 tence is known to us only by its effect viz., the production 

 of the various forms of intermittent and remittent fevers. 

 With regard to the real nature of the malarial poison, the 

 most generally believed opinion is that it consists of minute 

 organisms. Thus Niemeyer says : " I have no hesitation 

 in saying decidedly that marsh miasm malaria must con- 

 sist of low vegetable organisms." Certain it is, however, 

 that the microscope has not yet revealed them ; but as the 

 powers of this instrument are limited, as is the visual power 

 of our eyes, it is not, therefore, fair to assume that such 

 minute organisms do not exist. There is, doubtless, in the 

 personal constitution of certain individuals a peculiarity, 

 differing in degree in each, which predisposes them more 

 or less to the influence of the malarial poison ; and once 

 the disease has been excited, subsequent attacks may arise 

 without any exposure to malarial influence, thus proving that 

 its effect upon the constitutions of affected individuals is 

 invariably permanent, and that the individual who has once 

 been subjected to the action of malaria, will not only display 

 susceptibilities as long as his life lasts, but may pass them on 

 to his offspring by hereditary transmission. It must, there- 

 fore, appear that the state of body which we name diathesis 

 is capable of being produced by an agent so persistent and 

 permanent in its effects as the malarial poison. 



The Bronchocele Diathesis is, like the foregoing, depen- 

 dent upon certain climatic or telluric influences, and may 

 be either hereditary or acquired. Bronchocele or goitre 

 consists in hypertrophy of the thyroid gland ; but in reality 

 this is merely a prominent symptom of a general morbid 

 condition, which is endemic, and prevails in magnesian- 

 limestone districts. Its predisposing causes are hereditary 



