288 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



suit, the substance is not sufficiently solidified, and conse- 

 quently it contracts and acquires a dusky tinge, in some cases 

 becoming black. No indications of fungi were observed by 

 Mr. Berkeley. The disease has been attributed to sudden 

 changes of weather, and it is thought to be possibly of no 

 more than local development. 



MANGANESE IN BEECH-NUTS. 



It has lately been ascertained, in corroboration of experi- 

 ments made some years ago, but to which little importance 

 was attached, that beech-nuts contain a- large percentage of 

 manganese, although the soil in which they are grown may 

 exhibit no appreciable trace of this metal. 16 A,July, 1871, 

 402. 



NITROGEN IN MULBERRY LEAVES. 



Some important investigations were prosecuted, not long 

 since, by Dr. Reichenbach upon the chemical composition of 

 the leaves of the mulberry in connection with the silk-worm 

 disease, in the course of which he ascertained that such leaves, 

 as grown in Europe generally, had a much less percentage of 

 nitrogenous matter than those of China and Japan. He has 

 lately continued his inquiries by an analysis of leaves from 

 Turkistan, and has found in these an unusual percentage 

 of nitrogen, varying from 3.35 to 4.05 per cent, in the dry 

 leaf. 



In some accompanying remarks upon this paper by Liebig, 

 stress is laid upon the importance of such investigations in 

 determining d priori the value of different qualities of leaves 

 for raising silk-worms, and it is stated that where nitrogen is 

 deficient, the silk-worm suffers in its general health, and con- 

 sequently in its ability to produce a healthy and abundant 

 silk cocoon. The cause of the paucity of nitrogen in the 

 European leaves is believed to be the result of long-contin- 

 ued cultivation of the tree in the same soil, and especially 

 the use of leaves from trees that have attained their full size. 

 In a growing plant, as the roots are perpetually pushing out 

 into new and unexhausted soil, the proper supply of nourish- 

 ment is obtained; but the moment a complete development 

 of the tree is accomplished a diminution of nitrogen in the 

 leaves commences, with the results indicated ; so much so 



