These, in brief, are the high spots of the survey from the point of view of the scientist. In addition, I covered adjacent region of New Jersey to the west, including the Watchung Mt. range about Plainfield and the Oranges; the Bronx and Van Cortland Park and the country to Yonkers and the north, and to the northeast of New Rochelle. Long Island, as far as Hempstead, was also included. Altogether I travelled about 1200 miles on foot, not counting the distance traversed on trolleys and railroads. Always armed with opera glasses, I was careful not to use them when anyone was looking, for on the second day of the survey I had been arrested on the charge of being a German spy! I was also arrested on board a train in New Jersey for looking earnestly at a topographic map, then sharply out of the car window and noting what I had seen (dead chestnut trees) on said map. The carrying of a botanist's tin can (containing fungi, not bombs) was also an additional implicating circumstance on the latter occasion. What then were the results of the survey? They may be stated briefly as follows: 1. No immune trees were found. 2. For the most part the older trees (from 20 years upward) were entirely dead, and had been so for a long period, as attested by the bare trunks, weathered a characteristic gray color which only time can produce. 3. However, large numbers of seedlings and young saplings were located, both healthy and diseased. 4. _The most important result was the finding of three well defined colonies of living mature trees; all of which, by virtue of characters to be presently described, are offering more or less resistance to the disease._ SEEDLING TREES It is well known that seedlings and young saplings are naturally immune for a certain period, which varies in extent from 8 to 15 years beyond germination of the seed beginning, of course with the first formation of the seedling. Such immunity depends, however, not on any inherent characteristic, but on the fact that at this period the bark is usually smooth, sound, and free from wounds of any sort where Endothia spores and mycelium might enter. Of course, when wounded from any cause whatever during this period of youth, this immunity ends, so that the condition might perhaps be termed physical, in contrast to physiological immunity. As I have already said, large numbers of seedlings, for the most part still unattacked, were found in many places in the area surveyed. There are of course no grounds for believing that such seedlings, descended as they are from non-resistant trees, are physiologically immune. Where they are free from disease, this exemption is due merely to the physical immunity I have just mentioned. Since they therefore represent non-resistant stock, they were used for comparative inoculation work, which will be referred to later.