388 PHARMACEUTICAL BACTERIOLOGY 



8. Yellow fever can be prevented by destroying the specific carriers 

 of the disease, namely the Aides calopus. 



9. The Aides calopus (formerly Stegomyia calopus) must feed upon a 

 yellow fever patient during the first few days of the disease in order 

 that said mosquito may become a carrier of the disease. 



Insect powder (Pyrethrum) is employed to destroy mosquitoes in 

 houses. Sprays, crude oil, etc., are used on ponds, pools, and stagnant 

 water in yellow fever districts to destroy the mosquito larvae. Drainage 

 of wet lands, of swamps, of pools, etc., prevents the development of mos- 

 quitoes. Rain barrels and cisterns may breed the yellow fever mosquito. 

 Cold weather and frosts check yellow fever because the mosquitoes are 

 killed. 



The work of the yellow fever commission made possible the digging of 

 the Panama canal and yellow fever epidemics are a thing of the past. 

 The work of the commission is far better known and better appreciated in 

 Europe than it is in the United States. It should also be mentioned that 

 there were many others attached to the commission whose names are not 

 generally mentioned, as soldiers, nurses and attendants, who are deserving 

 of much credit for the success of the remarkable work done. 



K. Pellagra. Pellagra is a disease which has created great havoc in 

 Italy and other Eastern countries, and which first appeared in the United 

 States about 1907. It spread very rapidly and up to 1911 numerous cases 

 have been reported from the Southeastern United States and from Illi- 

 nois, with a few scattering cases from Kansas, Virginia, Pennsylvania, 

 New York, Massachusetts, California, and other states. The disease is 

 said to be caused by eating moldy corn (Zea mays) or foods prepared 

 from such corn. Ceni and others declare that the primary cause is a 

 species of Aspergillus (A . flavescens and perhaps also A . fumigatus) . It is 

 also believed that the ordinary household mold (Penicillium glaucum) 

 is a primary cause. The mortality rate is very high, and the disease is 

 said to be terrible in its effects. It first manifests itself as an eruption 

 of the skin usually appearing in the early spring, February or March, 

 after some variable prodromal symptoms. The skin becomes darkened 

 and blotchy. Eczematous eruptions next appear, with desquamation. 

 Gradually, as the older eruptions heal, while new ones form, the skin 

 becomes rough, from which the name,, pell' agra rough skin is derived. 

 The symptoms increase from year to year. The nervous manifestations 

 are varied and are accompanied by great suffering. 



Pellagra is not contagious or infectious, though the tendency is trans- 

 mitted from one generation to another. Childern of pellagrins are often 

 born with asymmetrical heads and various other deformities. They may 

 be idiotic or stupid and defective generally. 



