388 



o,onCmed to a ceuter of its o\v^». When tliey are treated to the action 

 of nitric, muratic, and nitro-muratic acids, no immediate change is ob- 

 servable ; and in those strong acids the life-like motion continues, which, 

 I think, proves that the motions are not the result of any form of or- 

 ganic life, but simply what is known as " Brownian motion," which is 

 frequently seen when minute particles of inorganic matters are placed 

 under a high x>ower. When the spores are combined either with con- 

 centrated sulphuric acid or caustic potash they become completely de- 

 stroyed, forming a homogeneous mass, and their organic structure is no 

 longer visible. 



^^^^'^ ^^' Plate 10 represents 



a sectional view of the 

 bark. Figure G, Nce- 

 maspora ; 7, the same, 

 wh en placed in water or 

 acid, except sulphuric; 

 8, a very highly magni- 

 fied form of the spores 

 contained in Fig. 6. 



About the 20th day 

 mycelium "was found 

 in abundance growing 

 from the spiral threads, 

 (see figure 5,) resem- 

 bling double-celled 

 Piiccinia, the spores, 

 varying in number 

 from 1 to 10, and so 

 small that a power of 

 one-eighth was re- 

 quired to give good 



definition, 

 tact "with 



Since con- 

 water dis- 



solves Ncemaspora without destroying the life of the spores, it is 

 evident that the action of rain or washes of pure water will only tend 

 to diffuse the spores over the body of the tree and roots, while the ap- 

 plication of solutions of sulphuric acid and alkalies will destroy them. 

 Hence a remedy may be found for peach-yellows in the application of 

 alkalies and sulphates, and their compounds, to the bark and roots of 

 the trees. Statements have frequently been made that the application 

 of hot lye has been known to cure i)each-yellows when applied to th3 

 bark and roots. My observations seem to confirm these common ru- 

 mors. 



In receiver No. 5 the healthy bark was not contaminated, seemingly, 

 with the Ncmiaspora, notwithstanding its immediate contact dur- 

 ing several weeks with the unhealthy bark. A& might be expected, the 

 common molds, Penieillium^^nCi Mticors, grew all over the surface of the 

 specimens, healthy and unhealthy. The leaves in Nos. 3 and 4 were 

 next examined. They had been subjected to the same treatment as the 

 bark. The healthy leaves, although confined during four weeks in a 

 moist atmosphere, at a temperature ranging from 80° to 90^, exhibited 

 no signs of mildew. A split branch to which the leaves were attached 

 exhibited a small portion of Mucor fruit, and JH^jcelium on the sap- 

 wood and pith ; but the unhealthy leaves were completely covered in 

 two weeks with Mycelium, (mold,) and the fruit of the common blue, 

 yellow, and black Fenicillmii and Miwors. I have repeated these ex- 



