85 



" We have planted the banks of the Fetzara," writes Riviere, " but the 

 plantation was required to be kept at a certain distance from the maxi- 

 mum limit of water, which increases suddenly owing to tho torrential 

 overflowing of the Oued-Zid and El-Aout into the immense basin. The 

 waters cover more than 34,580 acres, and are displaced by certain winds, 

 but the natural escape and the loss produced by rapid evaporation cause 

 immense miasmatic surfaces to be laid bare, thus producing, through an 

 absolutely direct isolation and rise of temperature, morbific elements 

 against which the recent plantations on its banks are quite futile. (Bull, 

 de la Soc, Nat. d'Aclimation, January, 1885). Riviere considers that 

 in these conditions it would be advantageous to plant bamboos first, in 

 order to circumscribe and to reduce by degrees the central basin. The 

 example of Ain Mokra cannot be quoted against the eucalyptus, it is 

 evident that it could not be expected to make the region completely 

 salubrious by planting eucalyptus upon the banks of such an immense 

 marshy surface as Riviere speaks of. 



The Eucalyptus Globulus is the best known of the euc dypti, it is that 

 which was first introduced into Europe, and is chiefly used in the old 

 plantations : in the new plantations the E. Globulus has been replaced 

 by the E. rostrata, mainly in Algeria. The E. Globulus does not resist 

 cold or great heat, it requires good ground, neither dry nor too wet, and 

 perishes rapidly in too marshy soil. The E. rostrata is more hardy. 

 (Riviere, op. cit ) 



Does the eucalyptus act simply as other vegetation by draining and 

 drying the soil ? If the soil is rendered more rapidly salubrious by it 

 than other trees, is it only because its growth is more rapid, or must it 

 be admitted that it has special virtues, and that it enjoys the property of 

 destroying the parasites of paludism ? This latter hypothesis is in itself 

 not unlikely. The eucalyptus, in fact, gives out aromatic vapours which 

 possess antiseptic properties, besides the leaves and branches which 

 cover the soil contain a large proportion of eucalyptol, which may prevent 

 the development of the germs of paludism. 



The influence of sulphur mines upon paludism has been pointed out 

 by d'Abbadie. It appears, from the facts quoted by him, that the sul- 

 phurous emanations which are produced in the neighbourhood of sulphur 

 mines have a favourable effect in palustral countries. (Commun, a 

 TAcademie des Sciences, September L8th, 1882). This action of sul- 

 phurous acid is easy to understand, unfortunately it does not seem that 

 it can be used to render localities healthy. 



In speaking of the individual prophylaxis I have already said that in 

 palustral countries it is necessary to watch carefully the drinking-water, 

 which seems to serve as the vehicle of the germs of paludism, to the 

 general rules for making a locality healthy, the necessity for providing 

 that locality with water of good quality must, therefore, be added. 



FERNS: SYNOPTICAL LIST.— XXVIII. 



Synoptical List, with descriptions of the Ferns and Fern- Allies of Ja- 

 maica, by G. S. Jenman. Superintendent Botanical Gardens, jDeme- 

 rara, ( continued from- Bulletin 5 ). 

 42. Asplenium Shepherdii, Spreng. — Root-stock, stout, erect, oblique, 

 paleaceous on the crown, stipites csespitose, f-L ft. 1. strong channelled, 

 the base dark and deciduously scaly, fronds pinnate or pinnate-pinna- 



