ALKALOIDS. 



ALKALOIDS. 



Kg., Chioniphe, Thienemann, Moulinea, Ch. 

 Robin, Enterobryus, Leidy, Eccrina, Leidy. 



PH^EONEME^;, containing the genera 

 Stereonema, Kg., Phceonema, Kg., Phceosi- 

 phonia, Kg. 



All these are byssoid or mucoid products 

 occurring in organic liquids undergoing fer- 

 mentation, vinous, acetous or putrefactive, 

 or in solutions of mineral salts, which are 

 likewise decomposed by them. They are 

 probably mycelia of various Fungi and not 

 independent organisms. 



BIBL. Harvey, Manual of British Algce, 

 2nd ed. 1849 ; Phycologia Britannica ; 

 C. Agardh, ' Sy sterna Algarum; 3. Agardh, 

 Species, Genera et Or dines Algarum ; Kiitzing, 

 Phycologia generalis; Species Algarum ; Ico- 

 nes PhycologictB ; Phycologia Germanica ; 

 Lyngbye, Hydrophytologia Danica; Greville, 

 Alga Britannica. 



ALKALOIDS. The utility of the micro- 

 scope in distinguishing the more common 

 alkaloids from each other, has been shown 

 in an able paper by Dr. Anderson. The 

 characters consist in the crystalline form of 

 the alkaloids themselves, and in that of their 

 sulphocyanides. 



The method employed consisted in dis- 

 solving the alkaloids in dilute hydrochloric 

 acid, and mixing the dilute solution, on a 

 glass plate, with solution of ammonia of 

 moderate strength if the alkaloid itself is to 

 be examined, or with a strong solution of 

 the sulphocyanide of potassium if the sulpho- 

 cyanide is required, and at once placing it 

 under the microscope. The only precaution 

 requisite is to avoid having the solution too 

 concentrated, as the crystals are then less 

 well-defined than if a dilute solution is em- 

 ployed. 



The power employed should be 250 dia- 

 meters ; for if a very high power is used, the 

 form of the crystals is not so readily distin- 

 guished. 



Atr opine is precipitated in the amorphous 

 state by ammonia, and not at all by the 

 sulphocyanide of potassium. 



Brucia. A salt of brucia in a sufficiently 

 dilute state, mixed with ammonia, does not 

 give an immediate precipitate; but in the 

 course of a very short time, irregular star- 

 like groups of pointed crystals are observed, 

 as in PI. 7- fig- 1 Solution of sulphocya- 

 nide of potassium produces a precipitate in 

 tufts of extremely thin and feathery crystals, 

 which either radiate from a centre, or present 

 a sheaf- like appearance. The latter form is, 

 however, much better marked in the crystals 



deposited after some hours from a dilute 

 solution, which are still microscopic, although 

 somewhat larger than those represented in 

 the figure. 



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, however, somewhat difficult to obtain 

 them well-marked, and they not unfrequently 

 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 (PI. 7- fig- 2). With 

 sulphocyanide 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 

 (PI. 7. 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 pre- 

 cipitate 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 (PI. 7. 

 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. The 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 of them are isolated, but 

 some cross each other at an angle of about 

 60. When lying in one position, they 

 exhibit more or less an appearance of a 

 St. Andrew's cross, arising from a peculiar 

 arrangement of some of then' facets (PI. 7. 

 fig. 5). The sulphocyanide consists of flat- 

 tened needles, sometimes single, but generally 

 in irregular groups, as in PL 7. fig- 6. They 

 are terminated by either 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 morphia; 

 but in the course of a longer or shorter 

 period, according to the degree of dilution, 

 crystals form, which gradually increase in 

 size, and possess the form represented in 

 PI. 7- fig- / Salts of morphia are not pre- 



