Summary and Conclusions. 



1. From the bacteriological experiments we have made and 

 the good results obtained from vaccination, we are of the 

 opinion that we have been dealing with one disease only. Owing 

 to the confusion in names which have been used to designate 

 this disease, we have concluded to give it a new name — Infec- 

 tious epitheliosis of birds (Epitheliosis infectiosa avium). This 

 indicates involvement of the epithelium both of the skin and 

 mucous membranes. It was thought that inasmuch as we find 

 so many variable forms of the disease that this name would 

 be more appropriate than any combination of names so far sug- 

 gested. 



2. Our work extending over a period of six years convinces 

 us that typical infectious epitheliosis is due to a combination 

 of two factors: (a) A filterable virus; (b) secondary invading 

 organisms which vary in kind but of which the so-called "Bacil- 

 lus diphtheriae columbarum" of Loeffler, appears to be the 

 most important. 



3. The filterable virus is the necessary primary invader 

 which lowers the bird's resistance and thus prepares the tissues 

 for the invasion by the secondary organisms. Neither factor 

 alone will cause the typical disease. 



4. The excellent results derived from the use of a vaccine 

 made from the secondary organisms, both in prevention and 

 treatment, are due to controlling the secondary infections which 

 cause the serious complications. If these are controlled infec- 

 tion due to the primary virus is mild and soon disappears. 

 (There is a remote possibility that the filterable virus is con- 

 tained in the vaccine. We have no evidence that this is or is 

 not the case. The presence of the virus in the vaccine would 

 indicate its growth with the other organisms on the cultures. 

 This would be contrary to our present knowledge of filterable 

 viruses. This point will be investigated.) 



5. The therapeutic dose, as indicated by the large number 

 of birds treated, is 1 cc. for the average adult bird. Younger 

 and smaller birds receive a lesser amount. 



6. The immunizing dose found most satisfactory is 1 cc. 



7. No bad results have followed when larger doses have 

 been administered. 



8. Reports received to date indicate that vaccination is 

 equally efficacious in the treatment of infectious epitheliosis in 

 turkeys. 



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