Yellow Fever and Other Diseases 115 



port the belief that egg infection is within the range 

 of biologic possibility. 



"If," says Dr. Dupree, "we admit contagious trans- 

 ference from mosquito to mosquito through the egg, 

 two questions present themselves : First, What pro- 

 portion of the eggs are thus endowed ? secondly, 

 How long can the hibernating or dormant egg retain 

 the infection in a virulent condition ? It is possible 

 that the infection will lose its virulence in wintering 

 over; it is also possible that it will not lose it at all, or 

 may do so partially, and thus produce mild, unrecog- 

 nised cases which, in their turn, may produce virulent 

 ones. In the present state of our knowledge, data 

 for answer to these queries are extremely meagre. 

 Parker, Beyer, and Porthier report that in mosquitoes 

 contaminated by feeding on a yellow-fever patient the 

 ova primarily take on a hypertrophy, but subsequent- 

 ly begin to degenerate until there is practically 

 nothing left but fibrous tissue. Were this true in 

 every instance, the possibility of ova infection as 

 a means of propagating yellow-fever would receive a 

 most positive and absolute denial. While we do not 

 question the accuracy of this observation, we must, 

 after the experiments of the American and French 

 Commissions, regard such degeneracy as excep- 

 tional." 



To establish the connection between the so-called 

 Myxococcidium stcgomyice, by some suspected of being 

 the " yellow-fever germ," Dr. Carroll made some ex- 

 periments. He found fusiform yeast cells in the 

 diverticula of a very few males of S. calopus in alcohol, 

 received from the Department of Agriculture. An 



