409 



has lately published the result of certain experiments made by him 

 upon potash as a nutrient of plants, the method adopted being one to 

 which we have already referred, and known as the " water culture." 

 The plants experimented upon were buckwheat and rye, although the 

 conclusions arrived at had reference more particularly to the formei\ 

 The solutions used were divided into those in which the potash was 

 completely excluded, or in certain cases replaced by bodies of similar 

 chemical properties, and into those in which potash is present, but in 

 different chemical combinations. The general conclusions reached were 

 that, in solutions free from potash, otherwise nutrient, the plants vege- 

 tated as if in pure water. Thej" were unable to assimilate, and exhibited 

 no increase in weight, for the reason that without the co-operation of 

 the potash in the chlorophyl grains no starch was developed. The 

 chloride of i^otassium was found to be the most effective form of combi- 

 nation under which the potash could be offered to the buckwheat plants ; 

 next to this came the nitrate of potash. With sulphate or phosphate 

 of potash, a disease was developed sooner or later, which, starting with 

 a ijositive heai^iug up of the starch, ended in preventing the starch 

 from being taken into the chlorophyl grains, and rendered useful in 

 vegetation. Soda and lithia were found incapable of replacing potash 

 in a j)hysiological point of view ; furthermore, while soda was found to 

 be perfectly useless to the plant, lithia, when introduced, proved to be 

 positively destructive to the vegetable tissues. 



Influence of ammonia on the color of flowers. — An experi- 

 ment was lately made by Vogel upon the influence of ammonia upon 

 the colors of flowers, in which eighty-six species and varieties were ex- 

 posed, under a glass bell, to a mixture of sal-ammoniac and lime-water, 

 the fresh flowers being placed at the same height in all the exi)erimeuts. 

 As a general result a difference was appreciable between the action of 

 the gas upon the colored matter deposited in grannies, and that forming a 

 solution, the effect being much less in the former than in the latter. In 

 most cases the changes produced agreed closely with those which the 

 coloring matter of the flowers passed through in the course of withering ; 

 and even in natural withering and fading there is the same difference 

 to be observed between the soluble colors and the granules. 



Orange FUNaus of bread. — At a late meeting of the Academy of 

 Sciences of Paris, specimens of bread, baked for tbe use of the army, 

 were exhibited, which had been rendered entirely unfit for food by the 

 development of a yellowish- white substance, changing gradually to an 

 orange-red color, and emitting a nauseous odor. Considerable agglom- 

 erations of this substance were formed, so as to fill all the cavities of 

 the loaf. When examined by the microscope, this appearance was found 

 to be due to the presence of a cryptogamic plant, already described as 

 Oidium anrantiaciim, and which was observed in the bread in Paris in 

 the summer of 1843, and at a later period at Marseilles and in Algeria. 

 The sporules* of the Okliuin were found to adhere to the husk of the 

 wheat, and were probably abundant in proportion as this was in a humid 

 state, badly cleansed, and had undergone alteration from the larvae of 

 the weevil, as it never occurs in bread of the best quality, carefully i3re- 

 pared. 



Wheat vs. flour. — In Dr. Moffat's paper on " Geological Systems 



and Endemic Disease," before the British Association, after pointing 



out that ansemia, goitre, and phthisis were more prevalent among the 



inhabitants of the carboniferous districts than among those living on 



3 



