SPONTANEOUS EXUDATION. 297 



interesting and important to deserve further attention. I am isea. 

 the more strongly of this opinion because I find that continental Uncertainties, 

 pharmacologists are by no means agreed as to the botanical 

 origin and place of production of the balsam, or even as to the 

 mode of its manufacture, one of the most recent writers 

 describing it to be obtained by boiling the bark and branches 

 or else by destructive distillation like tar; and two others 

 naming four species of Myroxylon as being probably employed 

 to yield it. 



Dr. Dorat, with whom I have interchanged letters occa- Dr. C. Dorat. 

 sionally for some years, and from whom I recently requested 

 information upon certain points connected with the history of 

 Balsam of Peru, thus replies to the inquiries contained in my 

 last letter : 



As I presume that you are writing a description of the balsam- 

 tree, I send you by return steamer the required answers to your 

 questions, together with a specimen of the naturally-exuded 

 resin, and a few beetles which are invariably found under any 

 part of the decayed bark of the Myrosperwium. 1 That no 

 possible mistake might exist on my part, I rode to Juisnagua, 

 it being still the collecting season, and took a sketch of the 

 process, which, w r ith a verbal description, will, I trust make all 

 clear to you. 



Now to answer your questions : as to the natural or sponta- Natural exud- 

 neous exudation. In young trees, say, until the sixth or eighth ation. 

 year, I have never seen any. After that age a greenish resin is 

 frequently found during the summer months on the northern 

 side of the trees when they are at rest, that is from December to 

 May. It is at first frothy and of a pale yellow colour, but as 

 it becomes hard it changes to green. It occurs in small 

 quantities and is difficult to get clean, as it is very sticky. It has 

 a slightly bitter taste, but no aroma. The Indians consider that 

 the trees which produce much of it yield an inferior balsam. 

 This, however, is only one of their many superstitions concerning 

 these trees. The largest quantity I have myself seen was upon 

 a very old tree ; it appeared in large tears lying one over the 

 other, almost like grapes. 



Early in the months of November or December, or after the Collection, 

 last rains, the balsam-trees are beaten on four sides of their 



1 Mr. Francis Walker, who has been good enough to examine this insect, 

 considers it identical with the Passalus interstitialis of Percheron. 



