CHARACTERS OF LATEX 47 



milk, usually exhibit very rapid Brownian movement 

 when a drop of the latex is examined with a microscope 

 under a high power. The globules vary considerably in 

 size in different latices, and even in the same latex the 

 range is often great, so that it is not surprising that the 

 measm^ements recorded by different observers show wide 

 variations. According to Seeligmann, the globules of 

 Para latex have a mean diameter of 00035 mm., whereas 

 Henri found them to vary from 00005 to 0002 mm. 

 Fetch has examined the latex from the stem of a twenty- 

 three-year-old Para tree gro^\^l at Peradeniya in Ceylon, 

 and according to his measurements the globules range 

 from 00005 to 0003 mm. in diameter, but he points out 

 that many of them had a distinct tail ; he further records 

 that the latex from a green shoot of the same Para tree 

 contained very minute granules, which were too small 

 to measure with a magnification of 600 diameters, and 

 a few globules about 0"001 mm. in diameter. Petch 

 also examined the latex of a Castilloa tree growing in 

 Ceylon and found the globules to range from 00015 to 

 0"003 mm. in diameter. He states that the largest 

 Hevea globules are the same size as the largest Castilloa 

 globules, but that the average size of the Castilloa globules 

 is greater than that of the Hevea globules. 



Fickendey found that the globules of Hevea hrasiliensis 

 latex varied from 0"0005 to 0001 mm. in diameter, 

 whilst those of Ficus elastica and Castilloa elastica ranged 

 from 0002 to 0003 mm. 



Jumelle has recorded the following measurements for 

 the globules in the latex of certain vines : Lamlolphia Per- 

 rieri, 0*0022 mm. (mean) ; Cryptostegia Tnadagascariensis, 

 0-0012 to 0-0023 mm. ; and Xylinaharia Reynaudi, 0-002 

 to 0-0025 mm. ; whilst Lecomte found the globules of 

 Landolphia owariensis latex to be 0001 mm. in diameter. 



The specific gravity of latex is usually a little below 

 that of water, and a large number of determinations have 

 been recorded for different latices giving values rangmg 

 from 0*956 to 0-997. The latex of Castilloa elastica 

 appears, however, to have a specific gravity slightly 

 greater than that of water : ColJens records values of 

 1003 and 1005 for two samples of the fresh latex in 

 Trinidad ; whilst Kaye gives 10 135 for a sample in Mexico. 

 Recently, too, Bamber in Ceylon found that a sample of 



