ALKALOIDS. 



[ 31 ] 



ALONA. 



dilute solution, wliich are still microscopic, 

 although somewhat larger than those repre- 

 sented in the ligure (PL 11. tig. 1, h). 



Cinchonine is obtained by precipitation 

 with ammonia in the form of minute granular 

 masses, made up of more or less distinctly 

 acicular crystals, radiating from a centre. It 

 is, hoAvever, somewhat difficult to obtain 

 them well-marked; and they not uufrequeutly 

 appear as a confused mass of granules, in 

 which the radiated structure is very imper- 

 fectly seen. They form best when the solu- 

 tions are rapidly mixed (PL 11. tig. 2). With 

 sulphocyauide of potassium, cinchonine gives 

 a precipitate consisting of six-sided plates, 

 together with a variety of irregular crystal- 

 line masses, and a few rectangular plates 

 (PL II. fig. 3). When formed by mixing 

 in a test-tube with agitation, and allowing it 

 to stand for some time, the crystals are still 

 microscopic, but much more definite, and 

 sometimes consist almost entirely of isolated 

 six-sided tables, of great regularity. The 

 precipitate dissolves readily in hot water, 

 and is deposited as the solution cools, in 

 irregular plates. 



Narcotine is precipitated by ammonia in 

 branched groups of pointed crystals (PL 11. 

 fig. 4). In concentrated solutions a preci- 

 pitate is thrown down by sulphocyanide of 

 potassium, which dissolves readily in hot 

 water, and is again deposited on cooling. 

 Under the microscope it is perfectly amor- 

 phous. 



Strychnine. Tlie hydrochlorate, treated 

 with ammonia, gives an immediate precipi- 

 tate, consisting of minute prismatic crystals, 

 all nearly of the same size and very well 

 defined. Most are isolated, but some cross 

 each other at an angle of about 60°. When 

 lying in one position, they exhibit more or 

 le.ss an appearance of a Saint Andrew's 

 cross, with a peculiar arrangement of 

 their terminal facets (PL 11. fig. 5.) The 

 sulphocyanide consists of flattened needles, 

 sometimes single, but generally in irregular 

 groups, as in PL 11. fig. 6. They are either 

 terminated by a blunt acumination or are 

 truncated. Those precipitated on the large 

 scale present the latter forms. 



Morphia. Ammonia does not produce an 

 immediate precipitate in solutions of mor- 

 phia ; but in the course of a Linger or shorter 

 period, according to the degree of dUulion, 

 crystals form, which gradually increase in 

 size, and po.ssess the form represented in 

 PL_ 11. fig. 7. Salts of morphia are not pre- 

 cipitated by sulphocyanide of potassium, 



unless the solution is highly concen- 

 trated. 



Quinine. Its solution gives with ammo- 

 nia a perfectly amorphous precipitate ; with 

 sulphocyanide of potassium small irregu- 

 lar groups of acicular crystals, resembling 

 those produced by strychnia, but longer 

 and more irregular (PL 11. fig. 8). When 

 the precipitate is produced in a test-tube, 

 and with a concentrated solution, it falls 

 immediately as a white powder composed 

 of extremely minute needles ; but when 

 the solution is dilute, it is deposited after 

 the lapse of twenty-four hours, in crystals 

 from 1-lth to l-3rd of an inch in length. 

 See Quininp: and Crystals. 



BiBL. Anderson (T.J, Edin. Mn. J. viii. 

 p. 570. 



ALLAN'TOIN.— A crystalline organic 

 substance found in the liquid of the aUantois 

 and in the renal secretion of the calf &c. 

 As artificially prepared, it is one of the 

 products of oxidation of uric acid. 



Its crystals form transparent colourless 

 needles and four-sided prisms, with mostly 

 dihedral unequal summits, PI. 10. fig. 20; 

 not very soluble in either cold or boiling 

 water, more soluble in alcohol, but not at 

 all in ether. 



BiBL. See Chemistry. 



ALLAN'TOIS. — An oblong or pyriform 

 sac developed during a very early period of 

 embryonic life from near the end of the in- 

 testine. Its function is that of a temporary 

 respiratory organ. The capillaries in the 

 aUautois of the chick are distributed closely 

 like those of the lungs of the Batrachia. 



BiBL. Wagner, Phys. by Willis ; Miiller, 

 by Baly ; Carpenter, Hum. Phys. ; Ivirkes' 

 Pln/s., by Baker. 



ALLOMOP.PHI'NA, Reuss.— One of 

 Peuss's " Cryptostegian "genera of perforate 

 Foraminifera. It has the appearance of an 

 irregular Miliola ; subtriangular, with the 

 chambers in a triple spire and overlapping 

 so much that only the last three chambers 

 are visible. The. aperture is a transverse slit 

 on the inner border of the last chamber. 

 Fossil in the Upper Chalk and Tertiary of 

 Germany. 



BiEL. Reuss, Denks. Akad. Wien, i. 352 ; 

 H. B. Bradv, Qu. Mic. Jn. xix. 67. 



ALLOT'RICHA, Kent.— A genus of 

 Infusoria, of family Ox-s-tricLina. 



BiBL. Kent, Infusoria, 18S0. 



ALO'NA. — A genus of Entomostraca, be- 

 longing to the order Cladocera and family 

 Lyuceidas. 



