Communications. 301 



substance of the fly is all destroyed. The tender and valuable 

 silk-worm has long been subject to epidemics, by which large 

 quantities have perished, causing such fluctuations in the price of 

 silk that the trade in this product has been frequently threatened 

 with a panic. The fungus, which is commonly called muscardine, 

 begins its growth within the body of the insect, soon to increase 

 in siz-3 and burst through the skin, thus producing death. 



One of the most curious of these insect infesting or carniverous 

 fungi grows upon or from the head of the larva of a certain species 

 of moth. It is an amusing sight to see the heavily burdened larva 

 bearing erect upon the front of its body a vegetable growth, often 

 three or four times its own length, the signal of distress as it must 

 be, telling plainly the slow but inevitable approach of death. 



Thus we have seen that the members of this peculiar group of 

 plants which has received the name of fungi, are all parasites, and 

 from their very nature do not increase the amount of organic 

 matter in the world, but on the other hand, are powerful reducing 

 ' agents, seizing upon that which is highly organized, and aiding 

 rapidly in its reduction to a more simple state. 



Though fungi furnish delicious articles of food, it is in the 

 light of their power to hasten decomposition that we see their 

 great importance in the world ; aiding in the cycle of life by facil- 

 itating decay. Sometimes they encroach upon our fields of grow- 

 ing grains and fruits, and do us serious damage ; but even here 

 the moralist would say there is a lesson of appreciation and care 

 for our crops, which only the school of sad experience is able to 

 teach. 



MINERAL CONSTITUENTS IN PLANT GROWTH. 



A paper presented by Prof. Gcessman to the Massachusetts Horticultural 



Society. 



A careful examination of the circumstances which have favored 

 the recent introduction of a more rational farm practice for the 

 production of crops, cannot fail to prove that the recognition of 

 the important influence which certain mineral constituents of 

 plants exert on plant grojvth in general has contributed more to 



