May 11, 1883.] 



♦ KNOWLEDGE ♦ 



281 



family, are found, as a rule, in the vicinity of reefs, or 

 above shallow places, playing in the sunshine. Their 

 beauty is very much heightened by motion. 



Heuglin says that in the Red Sea they are commonly 

 observed in the deep chasms or well-like depressions 

 between the coral reefs, -whore the water is always clear 

 and quiet, although there may be a high sea outside. 



When a ship anchors in a dark night between the reefs, 

 the presence of these fish may be perceived by their phos- 

 phorescence. 



They may be observed, often at a considerable depth, 

 faintly glowing spots ; suddenly they disperse like scat- 

 tering sparks, move slowly to and fro, gather together in 

 groups, and separate again. 



Nearly all the fishes of this family are carnivorous, 

 feeding upon small medusie, coral insects, iVc. These fish, 

 Heuglin says, play around the coral branches in the same 

 manner as birds hover around trees upon the land. 



In crowds thej' stand still for a few minutes before a 

 branch of a coral, suddenly dart forward, bite at the coral 

 insects on the branches, and hasten as if inspired by a spirit 

 to another place, to go through the same play, and begin 

 again the same chase. 



As soon as the archer fish sees a fly or any other insect 

 sitting upon a plant hanging over the water, it approaches 

 to within about one or one and a half metres (4 or 5 feet), 

 and spurts from its mouth a drop of water, so violently and 

 with such accuracy that it seldom misses its prey. 



It has this habit even in captivity, and the Japanese 

 make a household pet of it They keep the fish in water 

 basins, and place in the middle of the vessel a stick, some- 

 times reaching out over the water sixty centimetres (2 feet). 

 In the stick wooden pins are fixed, and insects are fastened 

 upon them. Soon after this is done, the fish swims around 

 the stick, comes up to the surface of the water, raises its 

 eyes toward the surprised insect, suddenly spurts a drop of 

 water upon it, throws it down, and swallows it if its shot is 

 successful ; if not, it swims around the stick and tries 

 again. The certainty with which they throw this jet of 

 water upon their victims is wonderful. 



In order to observe this, Hommel thrust a needle through 

 a fly and fastened it to the stick. Without intermission, 

 rapidly, and in regular order, all of his fish attempted to 

 throw the fly down, without once missing their aim as they 

 shot the drops of water upon it. 



Insects appear to be the most natural food for this species, 

 and seem to be preferred to every other kind of food. — 

 From Thierlebtn, by A. E. BreJim. 



keeping the tube cool while the electric light is burning ; 

 also for the introduction of water into the stomach to 

 distend the same. The lower e.\tremity of the tube is 

 provided with a platinum wire, which is made to glow 

 under the electric current, which is produced Viy a battery. 

 The tube is also provided with reflector prisms and lenses 

 for directing the light through the tube. 



The eye of the surgeon is applied at the upper end of 

 the tube, after it has been inserted in the stomach in the 

 manner indicated in our sketch. 



As preparation for the use of the gastroscope, it is 

 necessary that the patient shall have gone for some hours 



THE ELECTRIC LIGHT IX SURGICAL 

 DTAGNOSIS. 



WE find in a recent number of Annals of Anulonnj 

 and Surgeri/ a very interesting contribution by Dr. 

 Roswell Park, of Chicago, in which h(' describes the most 

 recent applications of the electric light for surgical pur- 

 poses. It appears that Josef Leiter, a well-known instru- 

 ment maker of Vienna, has at last succeeded in producing 

 electrical instruments by which the interior portions of the 

 human body may be strongly illuminated by the electric 

 light, and thoroughly e.\amined by the eye of the surgeon. 



The accompanying engraving shows the application of 

 one form of these new instruments, called the gastroscope, an 

 instrument for the examination of the stomach. It con- i 

 sists of a bent tube, which contains a window at one end, 

 electric wires, tubes for the introduction of a water cir- ; 

 culation, by means of rubber bags, for the purpose of 



without eating. Half-an-hour previous to its use a hypo- 

 dermic dose of morphia, say one third grain, should be 

 administered. Just prior to the examination the stomach 

 should be washed out. The patient is then laid upon the 

 left side on a table, having a head siipport, which shall 

 keep the neck in its axial position. A small receptacle is 

 placed under the mouth to catch the saliva which cannot 

 be swallowed. The head is then thrown well back, and 

 the instrument, which has previously been lubricated with 

 vaseline or glycerine, is guided by the finger of the left 

 hand, and passed downward with a gentle sweep. 



Previous practice on the cadaver with a hard rubber 

 sound of the same dimensions and flexure as the gastro- 

 scope will easily teach the necessary manipulations. The 

 instrument being in place, the stomach is inflated to the 



