NaturaU' Historical Collections'. 61 



Salmon-Trout of the Tyne and Tees, &c. ? and is it known by any other name 

 during its growth from the Fry to maturity ? 



20. Is the Parr met with in all rivers containing Salmon ? where and when 

 does it spawn ? Is it the same with the Brandling of the North of England, and 

 the Skirling of Wales ? It it supposed to be a perfect fish, or the Fry of some 

 species of Salmon ? 



21. What is the Grey {Salmo Eriox) of Dr. Fleming ? What are its states 

 from the young to the adult ? What are its migrations ? 



22. Are there are any species of migratory Salmon, distinct from those above 

 mentioned, known in the rivers of your neighbourhood ? 



Account of the Hya-hya, or Milk-tree of Demerara,* — We take an early op- 

 J)ortunity of presenting our readers with an account of the Hya-hya, or Milk-tree 

 of Demerara, from a tolerably full report of a letter from James Smith, Esq. to 

 Professor Jameson, in the Ed. Lit. Journ. No. 70. The notice may be complete, 

 but as it is probable that the letter will be published at length, in the Ed. New 

 Phil. Joum., we shall be able, in a future number, to give any additional informa- 

 tion it may contain. 



Mr. Smith, during his travels in South America, was constant in his inquiries 

 after trees yielding a milky juice, similar to the Palo de Vaca (or Cow-tree) de- 

 scribed by Humboldt. His Indian guides led him to a great variety, all of which, 

 however, had more or less of an acrid and deleterious principle, mixed with the 

 lactescent quality. At last, on an excursion up the river Demerara, he was told 

 by the native inhabitants of a settlement just below the first rapids, of a tree, cal- 

 led by the Indians Hya-hya, the milk of which was both drinkable and nutriti- 

 ous. The specimen of this plant, seen by Mr. Smith, had a trunk from 16 to 

 18 inches in diameter ; and was from 30 to 40 feet high, branching from the top. 

 The bark was grayish, slightly scabrous, and about a quarter of an inch thick ; 

 and the milk seemed to be secreted between it and the wood. The leaves were 

 elliptic, accuminate, smooth, and oppositely pinnate. -j- The flower was monope- 

 talous ; the calyx single, contiguous to the flower, and four-parted ; the peduncle 

 axillary, bearing four flowers, and sometimes five. The flower was sufficiently 

 developed to enable Mr. Smith to ascertain that it belonged to the class Pentan- 

 dria, and the order Monogynia. The tree had been felled before JMr. Smith saw 

 it, and having fallen across a small rivulet, the water was completely whitened by 

 its juice. The milk-like fluid was richer and thicker than cow's milk, and quite 

 destitute of all acrimony, leaving only a slight feeling of clamminess on the lips. 

 This viscosity it lost when drank in warm coffee, with which it mixed freely, and 

 appeared incapable of being distinguished from animal milk. A portion of the 

 juice, preserved in a bottle, did not begin to curdle till the seventh day after it 

 was taken from the tree ; and on the twelfth day, some of it was used by Mr. 

 Smith in tea, without its being distinguished from animal milk by those who 

 drank it. The Hya-hya is said to be by no means uncommon in the woods of 

 Demerara ; and there is reason to hope that its fruit may soon be procured. A 

 dried specimen of the plant, and a small bottle of the milk, were transmitted by 

 Mr. Smith to Professor Jameson, along with his letter. The latter is now under- 

 going a chemical investigation ; the former was exhibited to the meeting of the 

 Wem. Soc. accompanied by descriptive notes from the pen of Mr. \^''alker Arnott. 

 This gentleman referred the Hya-hya to the natural order of ApocynecB, and the 

 genus Taberna-montana — under the name T. utilis. " The usual properties of the; 

 milk of the Apocynece," continued Mr. Arnott, " are deleterious, and it is rather 

 remarkable to find an instance to the contrary in this tribe ; and I do not think 

 there is any other on record. Future observations may however, perhaps, ascer- 



" Read before the Wernerian Society, Mar. 6, 1830. 



i* Though this report bears the evidence of an authentic source, we presume 

 that this should be written opposite, as we are not aware of any of the Apocy- 

 neae having oppositely pinnate leaves. 



