120 Brand in the Cereals. [Sept., 



belonging to this country. The great idea of De Candolle " the 

 spreading of the species of brand depends on the sowing of the 

 spores," since the beautiful observations which Gleichen publish- 

 ed more than sixty years ago, can no more be doubted. This 

 great German natural historian found indeed that the wheat crop 

 strewn and sown with brand dust gave over 50 per ct. of ears af- 

 fected by brand, while the dry and thoroughly washed seed ex- 

 hibited scarcely any ears aifected by brand. 



Besides many eutophytes may be transported, and in the kinds of 

 brand of grain w^e are by no means justified in denying the trans- 

 mission by spores, and especially as no husbandman can maintain, 

 " that he has cultivated wholly clean seed containing not a single 

 brand-spore;'' for in practice the extraordinary minuteness of the 

 brand-spores lays an insurmountable obstacle in the way of all 

 observations. The parasites which have their abode in the dead 

 parts of plants may easily be propagated by the sowing of their 

 spores, and a careful observer may in this latter case readily fol- 

 low^ the germ of the spores sown, and the gradual development of 

 the parasite tlu'ough all the stages of its formation, as I have al- 

 ready many times shown in other places. But a multitude of eu- 

 tophytes besides the sowing by spores also require peculiar condi- 

 tions of soil and a moist atmosphere for their development; since 

 otherwise the mother plant is not capable of furnishing the nutri- 

 tion indispensable for its development, or to perform the secretion 

 of the same from its own fluids. 



These organic processes necessary to such formations, are yet 

 partially mysteries to natural historians, which may not be laid 

 open by logical phrases, or such as belong to natural philosophy. 

 Only direct observations can here determine, and all views, opin- 

 ions, belief and so-called experience are positively injurious, while 

 they are almost ever wanting in any strong induction, and under 

 critical examination sink into their original nothingness. It is 

 therelbre the wiser openly to admit that we have not yet observ- 

 ed the direct propagation of the kinds of brand by spoies, as we 

 must allow on a critical investigation of all circumstances, ^' that 

 the conditions of soil, the injlnence of cultivation, weather, situa- 

 tion and manure which is required Jor the sjyreading of the various 

 species of brand, are not fully known." Such conclusions are 

 more salutary for the advancement of human knowledge, than all 

 the so-called learned or purely empirical talk. 



But since Ehrenberg has practically demonstrated the propaga- 

 tion of the infusoria by eggs and division, and I have also the 

 sowing of fungi and mushrooms by spores, we may too hope for 

 a similar proof of the propagation of eutophytes by spores, and 

 until then set aside all speculations on their spontaneous generation 



