﻿28 MIJSGRAVEL 



other cases and a similar appearance of the abscesses of tubercular origin is more 

 decided than it is usually. Tubercle bacilli and the eggs of P. westermanii were 

 found together in some of the lesions. 



Cases Nos. 9 to 11. — These are all cases which have only been observed clin- 

 ically, in which the diagnosis has been made by the "finding of the eggs, either 

 in the sputum or stool. These eases will not be reported in detail but the 

 more or less careful clinical findings will be embodied in their appropriate places 

 in this paper. 



VI. ETIOLOGY. 



A. CONTRIBUTING CAUSES. 



The contributing causes which bring about infection with this or- 

 ganism, of course, can not completely be elucidated until the life cycle 

 of the parasite has been full}- worked out. However, a number of points 

 deserve consideration. 



(a) Geographical distribution. — In the opinion of some of the best 

 zoologists, not all of the parasites which have been rej)orted as Paragon- 

 imus are of the species westermanii. but until such time as this confusion 

 is made more clear, it seems advisable to consider the geographical distri- 

 bution of this disease as including all points from which the parasites have 

 been reported either for man or other animals. Considered in this 

 broad sense, the geographical distribution would include practically all 

 of Japan, points in Korea, Formosa, China, Holland (Amsterdam), 

 Germany (Hamburg), Sumatra and the United States, and to this list 

 the Philippine Islands must now be added. It is almost certain that 

 the increased interest which the importance of this subject demands will 

 result in the finding of the infection in many places where it has hitherto 

 been unsuspected. 



(6) Age, sex, race, occupation, climate, axd personal habits. — 

 Age is probably not a factor in the etiology of the disease, excepting to 

 the extent that, as in many other infections, the exposure is greater and 

 the infection correspondingly more frequent during the more active years 

 of life. Stiles from the statistics up to 1900, compiled 59 cases, 45 of 

 which were between the ages of 11 and 30 years. Four cases were in 

 children under 10 years of age and one in an individual over 50 years 

 old. My 17 patients ranged from 20 to 62 years of age. Eleven of 

 them were between 25 and 35. 



Sex. — The disease is much more frequent in males than in females. 

 This has been noted by several Japanese observers and in a recent con- 

 versation with me. Professor Tokishige again emphasized this fact, at 

 least in so far as Japan is concerned. Stiles and Hassall's statistics 

 show 58 males out of 66 cases. My cases have all been In males, but it 

 must be understood that in compiling this series my opportunities for 

 observation have not been such as to allow me to judge in regard to 

 females. 



