235 



been carried so far that some of the companies doing business on 

 the Isthmus of Tehuantepec, where there is a very distinct dry- 

 season, still feel it necessary to omit this fact from their prospectuses 

 or to represent their plantations as always moist. The incorrect- 

 ness of this claim not then being realized, the extent of the dry 

 season of the west coast of Guatemala and the adjacent Soconusco 

 district of Mexico was observed with much interest. 



GREATER ABUNDANCE OF CASTILLOA ON THE DRIER PACIFIC SLOPE. 



The total rainfall of a place affords but the slightest intimation 

 of its climate in relation to vegetation. A sudden, heavy shower 

 may wet the soil much less than the same amount of water falling 

 as a steady rain, and in the supply of water to plants the difference 

 is even greater ; the period during which the atmosphere and soil 

 are moist is of importance to them, but not the amount of water 

 which patters off their leaves or falls into the rain-gauge. Humidity 

 even to the point of saturation for six months may be of no avail 

 to plants unable to survive an equal period of drought. The low- 

 land forests of the west-coast districts of Guatemala and southern 

 Mexico, while composed in the main of the same tropical elements 

 as those of eastern Guatemala, yet showed a striking deficiency of 

 plants requiring continuous humidity.* Nevertheless wild Castilloa 

 seems to have existed in the past as in the present in far greater 

 abundance, the wild product having long been an article of export 

 in quantity far more considerable than from the eastern districts. 



FREER FLOW OF MILK IN DRIER REGIONS. 



A second fact contrary to the popular supposition that rubber 

 production is confined to continuously humid climates was 

 encountered when it was found that, in spite of the greater dryness, 

 the milk flows down from the rubber trees of Soconusco with a 

 freedom unknown in eastern Guatemala, where it merely oozes out 

 into the gashes made by the "uleros." Dr. Paul Preuss, who 

 studied rubber culture in Trinidad, Mexico, and Central America 

 for the German Colonial Society, did not see rubber flow down 

 from the wounds made in tapping, and seems to have left America 

 in some doubt as to the reality of this phenomenon. He explains 

 that the milk of Castilloa behaves very differently from that of 

 other rubber trees. The " fishbone cut" to which he had been 

 accustomed was found in Trinidad to be useless with Castilloa, 

 since the milk flowed out as a liquid only in the first few drops 

 and soon turned into a pulpy mass, which remained in the grooves 

 and had to be wiped out with the finger. Dr. Preuss says : 



In a Castilloa plantation near San Salvador the manager stated, on my inquiry, 

 that there are hiile trees the milk of which is completely liquid and others of 



* Such are the filmy ferns, or Hymenophyllacec-c, and forest species of Selaginella ; 

 also many Orchidace.-c and Piyieracea\ larj^ely absent from the forests lietwcen Ayutla 

 and Tapachula, and also from the vicinity of La Zacualpa. Moisture-loving plants in- 

 crease with altitude iis the more humid collee districts are approahed, but at no lowland 

 locality visited do they exist in any such abundance as in the forests of (he valley of 

 the Polochic River, in eastern Guatemala. 



