1. The disease was almost certainly infectious.

2. Its eradication offered much greater practical difficulties than are presented by certain other infections of mice.

3. A definite tendency toward greater susceptibility in first litters as contrasted with subsequent ones was noted.

4. Advantage could be taken of this increasing resistance to keep the infected colony in efficient production, but accidental loss of the stock prevented the continuation of the plan for a time sufficient to exclude possible failure due to seasonal variation.

5. Multiple etiologies may well have existed even within this circumscribed outbreak.

6. Experimental investigation of the condition offers extraordinary difficulties but its thorough understanding promises to bring new light to basic problems of disease.