70 On Smut in Wheat, 



will produce misseltoe the following season. Therefore 

 instead of placing the smut in mould, it may be more 

 adviseable to introduce it into various parts of a plant 

 of wheat, as the stem, and the ear in various stages of 

 vegetation, from the milky state of the grain to its com- 

 plete maturity. 



The first experiment may serve to shew whether the 

 products yield azotic phosphoric or carbonic gas ; or a 

 fixed or a volatile alkali, and consequently whether they 

 partake most of the animal or vegetable nature : finally 

 the products should be compared with those of sound 

 wheat. 



The second may shew whether it contains any visi- 

 ble marks of organization, as the seeds of vegetables or 

 the ova of insects. 



The third whether any of the particles can be made 

 to bring forth insects in the embryo state, or clusters of 

 minute fungi, as in the mildew, w^ich are visible in a 

 very good microscope. 



The black powder of the puff ball, which bears no 

 small resemblance to the smut of wheat, contains the 

 invisible seeds of the plant, which are buoyant in air, 

 and float in the atmosphere till they descend to the earth 

 with rain or dew, to be deposited in the soil. The seeds 

 of the parasitical fungus, which insinuate themselves 

 into the pores of the stem or leaves constituting the mil- 

 dew, are alike invisible to the naked eye, and are pro- 

 bably disseminated in the same way, as are also the other 

 minute seeds of the fungi, which belong to the crypto- 

 ^amia of Linnseus. The mildew commonly exhibts a 

 yellow powder, but Sir Joseph Banks observes another 

 species which consists of a dark brown or chocolate co- 



