MICROSCOPIC INVESTIGATION. 



195 



in composition, a watery juice is always formed wbere the fungi rested. 

 ^Yhenevo^ the conditions are favorable for aquatic life, it appears in 

 profusici!. This explains the cause of its rapid decay in the field, when 

 once attacked by " mildew and smut,"' under high temperature and 

 moisture. 



Moisture, and a temperature of about 70°, seem to have the efiect of 

 changing the sectional spores from their original appearance, as repre- 

 sented in Fig. 18, 2, to that in Fig. 19, 10, in which a greater number of 

 divisions is observed, containing sometimes as many as eleven cells, and 

 all containing slightly elliptical spores. To ascertain the true course of 

 the transformation of the onion-blight and smut will require further ob- 

 servations ; but I think it probable that the so-called smut is but a 

 higher stage of the secondary globular yellow fruit seen on the mycelium. 

 See Fig. 18, G. The micro-chemical observations made fully sustain the 

 views of the onion-growers, viz, that the onion-smut is verv tenacious 

 of life. 



In many localities, rank weeds might be procured in great abundance 

 on fields infested by the fungi, (on the field alluded to, weeds three feet 

 in height grew in profusion;) v.ero they cut down, sun-dried, spread 

 over the field, and with them brushwood and all useless materials found 

 about the fiirm burned, the surface-spores, and all germs of a parasitic 

 life within reach, would be consumed, and caustic potash, lime, and 

 charcoal would be liberated and diffused over the field for the benefit of 

 the succeeding crops. 



YELLOWS OF THE PEACH. 



On the 1st ot July last I commenced a series of experiments by the 

 moist process with the bark of a peacb-treo affected with, the yellows. 

 Into five glass receivers I idaced respectively, a few drops of water, 

 just sufiicieut to form a moist atmosphere in each. Into No. 1, I put a 

 piece of bark aiiected with the yellows ; into Xo. '2 a piece of bark from 



a healthy peach-tree ; 

 into iSro.3 a handful of 

 peach-leaves from the 

 unhealthy tree; into 

 Xo. '1. a similar quan- 

 tity from the healthy 

 tree; and into Ko. 5 

 portions of bark from 

 the healthy and un- 

 healthy trees mcu- 

 tioued. All the spec- 

 imens were secured 

 from the outward at- 

 mosphere. The tem- 

 perature of the room 

 in which the speci- 

 mens were kept was 

 frequently at 90° Fah- 

 renheit. These condi- 

 tions were highly fa- 

 vorable to the de- 

 velopment of such 

 fungi-germs as ma- 

 ture under excess of 

 the specimens in the re- 



thca and moisture. Previous to arrauaino; 



