216 



for comparison. It is however intended to carry out a series of trials 

 (already started) at Biver estate by which it may be ascertained what 

 is really the average weight, when dry, of 100 lbs. of wet cacao. 



Deductions made from experiments which extend over short 

 periods only, are apt to mislead, rather than to inform ; as the results 

 of one year may not compare with the next, although each has its 

 value in the aggregate taken from the results of several years. It is 

 proposed therefore to await the returns from such plots, until at least 

 three years has elapsed, when the value of the experiment will be 

 more plainly seen. 



An opinion may however be recorded without prejudice. Mr. 

 De Verteuil writes : — " Next year I think will show vp better, as the 

 trees have certainly a healthier look on the manured plots than on the 

 unmanured one.''' 



Such an opinion is of value as coming from an experienced 

 planter, and one accustomed and fully competent to judge the condi- 

 tion of a cacao tree. 



717.-THE GROWTH OF PLANTS WITHOUT CARBONIC 



DIOXIDE. 



M. Lefevre has recently contributed a paper to the Academie 

 des Sciences upon the development of plants exposed to light but 

 entirely deprived of Carbonic dioxide in an artificial soil containing 

 amides (crystalizable substances allied to ammonia but containing 

 less water). He begins by observing that the carbonic acid of the 

 atmosphere is not the only source whence green plants may derive 

 their carbon. By a series of experiments. M. Lefevre proved that in 

 soil containing a suitable quantity of amides green plants could be 

 developed though deprived entirely of carbonic acid gas. The plants 

 increased to five or even ten times their height multiplied their 

 leaves, and the tissues were formed normally. When both carbonic 

 acid and amides were absent the growth was arrested. Therefore 

 growth under a glass in soil containing amides is affected by a process 

 of nutrition.— Extract " Gard. Chron." 



2nd September, 1905. 



718. -MANGE IN CATTLE. 



DEFINITION. 



Mange is a contagious skin disease caused by parasites belonging 

 to the class of psoric acari. 



Three forms of mange occur in cattle, viz., sarcoptic, jisoroptic, 

 and symbiotic. These forms are named after the variety of parasite 

 which is the cause of the ailment. Sarcoptic mange in cattle is un- 

 common. The most prevalent forms are the psoroptic and symbiotic, 

 and these frequently exist together in the same animal. Cows are 

 most often attacked. 



