i8: 



HARD WICKE'S SCIENCE- G OSS IP. 



medicinal properties, however, are due to the pre- 

 sence of the alkaloid morphia. 



It is one of the most valuable of all drugs, and is 

 used with advantage in an immense number of con- 

 ditions, — to relieve pain, allay spasm, produce sleep, 

 prevent restlessness, promote perspiration, &c. 



Arnotto. — This, to some extent, important colour- 

 ing agent, is obtained from the seeds oiBixa orcUana, 

 Linn., originally a native of tropical America, by the 

 side of rivulets and streams, but now cultivated through- 

 out the tropics. It is a small tree, with a stem from 

 12 to 15 feet in height. Leaves cordate-peltate, taper- 

 ing at the apex, smooth, on long petioles. Flowers 

 in terminal panicles, pale pink ; stamens numerous. 

 Fmit bristly, two-valved, many-seeded. Seeds angu- 

 lar, covered with an orange-red waxy pulp. The 

 pulp surrounding the seeds is the important part in 

 an economical point of view. It has the smell of 

 violets, and is bitter and astringent. A refreshing 

 decoction is prepared from it, which is considered 

 febrifugal, and is also used in cases of haemorrhage, 

 gravel, diarrhcea. The aromatic bitter seeds and 

 root are reputed stomachics. So much for its " re- 

 puted " medicinal properties. 



To obtain the arnotto, the seeds are steeped in 

 water, and allowed to fei-ment ; it then forms a valu- 

 able red dye, which by evaporation becomes a solid 

 paste. This is made into cakes or rolls, known as 

 arnotto or annotto. It is largely used by silk-dyers 

 and varnish-makers, also for colouring cheese, butter, 

 chocolate, &c. It was formerly considered an anti- 

 dote to the poison oi Jatrop]ia ]\IantIiot . The Carib- 

 beans formerly tattooed themselves with it to prevent 

 mosquito-bites. 



A MICROSCOITCAL SLIDE-BOX. 



THE old cloth-covered microscopic slide-boxes, 

 that we all know so well, have to this day 

 some advantages possessed by no others. They take 

 a large number in a small space, and, with a dozen 

 or two slides, go easily into the pocket. They are 

 unequalled for carrying about, but possess, as sta- 

 tionary boxes, this serious drawback, tliat each slide 

 rests upon one edge, giving the object a great ten- 

 dency to slip. 



The newer tray-boxes are a great improvement 

 upon these, in that all the slides lie flat. But 

 it is very awkward when you happen to want a par- 

 ticular slide, and do not remember exactly in which 

 tray you put it, to liavc to pull out a number of trays 

 before you come upon the one containing the slide 

 you want. Cabinets are well enough for home use ; 

 but are not portable, and labour somewhat under the 

 same disadvantage as the tray-boxes. 



There is great need of a box in which each slide 

 may lie flat, and be kept in its place whatever tempo- 

 rarily may be the position of the box, one into ^hich 



the name of every slide may be seen at once, and any 

 slide be taken out without disturbing any other. 



Such a box, I think, is shown in the accompanying 

 drawings. Fig. 152 gives a general perspective view, 

 and fig. 153 shows a section of the same. 



It consists of a box opening in front and at the top, 

 like the tray-slide box ; but here the trays, or rather 

 shelves, are fixed, and have no front ledge. Each 

 shelf projects a little beyond the one above, and is 

 divided along its length by thin slips of wood into 

 spaces, each just wide enough to take one slide. The 



Fig. 152. Perspective view of Microscopical Slide-box. 



Fig. 153. Section of Microscopical Slide-box. 



piece marked A in both drawings is a piece of card- 

 lioard, or wood, loosely jointed to the lid, v,. This, 

 when the box is open, lies flat upon the lid, i! ; though 

 it is drawn in the illustrations projecting, in order 

 better to show its position. When the lid B, and the 

 front, E, are closed, the piece A falls down, so that its 

 lower edge rests in the angle formed by the bottom of 

 the box and its front, E. It therefore lies fixed against 

 the front edges of all the slides ; so that if the box be 

 placed on its end or upside down, the slides cannot 

 shift, and will be found each in its place when the 

 box is righted and opened. The slides project in 

 front \ inch beyond the shelves, so tliat with the 

 finger and the thumb, applied either laterally or ver- 

 tically, any slide may be instantly removed. By 

 making the shelves project \ inch, the labels on every 



