85 



quite firmly convinced that this action is due to the pr sence of a 

 clottinc t nzyme. This assumption is made" probable by the fact of the 

 quite universal presence of I'ectin in plants, and further from the fact 

 that I have proven the presence of calcium salts and pectic compounds 

 in the latex of the papaw. This statement is fun her strengthened by 

 my observation that the latex of the papaw will coagulate the juice 

 (neutral or alkaline) of certain oth' r p'ants The pr sence of renn-n 

 ferment in the latex of the papaw is noted elsewhere in this paper. 

 Its behaviour is, in many respects, unlike that of the jelly-fotming 

 enzyme here noted, and, while further examination of fresn materi;il 

 is needed before making anv fuller statement, I think 1 am safe in an- 

 nouncing that we may add the papaw latex to the list of plant juices 

 in which the pectase ferment h s been noted. 



The odour of the fresh milk is pronounced, and not unlike that of the 

 latex of the india-rubber tree, and on the whole, is a disagreable one, 

 suggestive of decayed meat The taste i-^ somewhat b tter, rather 

 markedly astringent and acrid. When dried by artificial heat the fer- 

 ment power is weakened or lost, if dried in the sun it retains its 

 activity and about 75 per cent, of moisture is se^parated. 



This milky emulsion seems to be secreted for the most part in 

 fairly large vessels (readily observable by a pocket lens), which lie 

 just under the epidermis in every part of the plant. In the ripened 

 fruit it seems to permeate to all parts of the fleshy portion of the fruit 

 (somewhat changed in character). The supply of milk in a vigorous 

 tree is very abundant After making several prolonged incisions in a 

 single fruit, I estimated that an entire- tree must contain several hundred 

 ounces, but no such amount can be ob ained by any practical method. 



The dried milk of the papaw is an article of commerce, and its 

 character is dependent upon the method of preparation. I'he main 

 source is the crude method of the natives. The usual proceeding is to 

 make an incision just through the rind of tKe green fruit ; the milk 

 flows freely for a short time ; this is caught in a dish, coagulation 

 follows closely, and the milk o zes slowly through the incision for 

 twenty-four hours or more. If numerous incisions are made in the 

 fruit, it will, at the end of this time, become ^ an inch thick. The 

 milk is most abundant after heavy rainfalls, from the first fruits of the 

 tree, and naturally so from vigorous plants. 



The latex, when allowed to dry on the fruit, becomes discoloured and 

 dark. The lighter- coloured and best products are produced when the 

 coagulated juice is removed as fast as it exudes, spread out thii and 

 quickly dried. 



No adviintageous method of gathering the milk has come under my 

 observation. Some of the difficulties of the present usages can be 

 imagined by the recollection that in some cases the fruits are from 20 

 to 30 fent from the ground. The coagulation allows only a small 

 yield, requiring constant climbing to make fresh incisions. The latex 

 yields 25 per cent, of dried material (still containing 6 to 10 per cent, 

 of moisture.) Under favourable conditions I extracted 100 grammes 

 of latex from one fruit. One gatherer claimed an average yield of 

 one pound of dried milk from each tiee per year, though under some- 

 what adverse conditions it required fifty trees to yield one pound of 

 dried milk. 



