DEVELOPMENT OF THE MIRACIDIUM OF PARAGONIMUS. 183 



Cultures were then left dry for from one to several hours, with the 

 same results. 



Finally, cultures in petri dishes were carefully watched until the last 

 water had evaporated and the sediment was left dry in the bottom. After 

 a short interval, which approximated and certainly did not exceed ten 

 minutes, fresh water was added. When examined under the microscope, 

 the shells were shrunken and the cellular contents broken down and 

 though the cultures were kept under observation for several weeks after 

 the control-cultures had developed motile miracidia, no development 

 occurred in those previously dried. 



It would seem safe to conclude, therefore, that desiccation, even for a 

 few moments, is fatal to the life of Paragonimus eggs and that the ova 

 can not be disseminated otherwise than in water. 



The theory which has been broached that infection of man might 

 occur by means of ova blown about in the air, even though there were no 

 other objections to it, would appear to be absolutely excluded by the 

 failure of the ova to withstand drying. 



REFERENCES. 



For complete bibliograpliical references to articles quoted see Stiles and Hassall, 

 Index Catalogue of Medical and Veterinary Zoology, Bulletins of Bureau of 

 Animal Industry, Washington, D. C. 



