KIDD'S OWN JOURNAL. 



97 



THE WONDERS OF NATUEE. 



PARASITES. 



In these beings so minute, and as it were 

 Such non-entities, what wisdom is displayed! 

 What power ! what unfathomable perfection ! 

 Puny. 



MONGST the wonders of crea- 

 tion, there is a large class of ani- 

 mals whose very existence is 

 unknown to the majority of 

 mankind. Indeed most of them 

 are so minute, that they can 

 i only be seen with the help of a 

 microscope ; and, had it not been for this in- 

 valuable instrument, we should never have 

 become acquainted with the tiny population 

 of our globe. They are a world within a 

 world. We now allude to those creatures 

 called parasites, because they cling to and feed 

 upon the bodies of other living creatures. 

 They consist of a great number of species, 

 and are of endless variety of form and struc- 

 ture. Their food and habits are as diversi- 

 fied as their places of habitation. These pa- 

 rasites infest every animal, and every organ 

 of the body. They are found thriving in lo- 

 calities where no person would expect that 

 they could live. They fatten uponjthe eyes, 

 the blood, the gall, the bladder, the liver, the 

 intestines, the kidneys, and all the muscles of 

 the corporeal frame. They cast their grap- 

 pling hooks in the mouth and jaws of the 

 most voracious animals, and pursue the un- 

 wearied operation of sucking their juices, in 

 spite of all the whirlwinds and earthquakes 

 that are going on around them. Nay, they 

 even find entrance into the brain, and unce- 

 remoniously take a seat upon the throne of 

 sense and understanding. The operations of 

 most of these parasites are unfelt and unper- 

 ceived ; though there are larger and irritating 

 ones, especially of the louse genus, which we 

 shall not attempt to describe. 



Many of our readers will scarcely believe 

 us, when we tell them that three hundred and 

 sixty little worms have been taken out of a 

 single eye of a perch. Each of these ani- 

 mals had a perfect organisation ; having 

 organs for taking and digesting its nourish- 

 ment, and for propagating its species. This 

 minuteness of the animal world will appear 

 more extraordinary, when we add, that such 

 parasites are themselves infested with animal- 

 cules still more diminutive. A certain monad 

 feeds upon them, as they do upon the juices 

 of the perch's eye ; and perhaps these monads 

 have their attendant leeches. But human 

 curiosity has its limits ; and though the mi- 

 croscope discloses wonders within wonders, 

 yet it at length leaves us in the depth of our 

 researches, amazed at what we have seen, and 

 imagining what may still remain undiscovered 

 beyond the curtain of sight. 



The structure of insect parasites is skil- 

 fully adapted to the various situations in 

 which they are placed ; some of which are 

 very strange and hazardous. Another para- 

 site which infests a different part of the fish 

 to which we have already alluded, has been 

 minutely described by Dr. Nordman. Some 

 people have wonderful patience and tact for 

 investigating the forms and habits of the crea- 

 tures which people the microscopic world ; 

 and they think themselves well repaid for 

 their trouble, by the new exhibitions of crea- 

 tive wisdom which they perceive in every new 

 discovery. The doctor has made us acquaint- 

 ed with a parasite which he denominates 

 Actheres percarum, or, pest of the perches. It 

 is a fresh-water insect ; but, instead of floating 

 about in the liquid fields of nature, and enjoy- 

 ing the free exercise of liberty, until engulfed 

 by some superior of the finny tribe, it boldly 

 enters the mouth of the perch, and extracts 

 nutriment from the very masticating organs 

 of this voracious fish. As the perch is noto- 

 riously greedy, and often swallows its prey 

 entire, the contortions and pressure of its 

 mouth must sometimes be very great. Yet 

 the Actheres hesitates not to attach itself to 

 the palate, and even to the tongue, of this 

 gormandiser. It therefore needs a very 

 strong anchorage when it stations itself in 

 the vortex of such aCharybdis. Nature has 

 provided for this emergency. The Actheres 

 is provided with two strong arms, proceeding 

 from the base of its cephalothorax, or that 

 part of the head which also serves for a neck ; 

 and these taper, like the trunk of an elephant, 

 till they unite in a single sucker. The crea- 

 ture buries his organ so deep into the cellular 

 membrane of the perch's mouth, that it can 

 neither disengage itself, nor be extracted by 

 foreign violence, without rupturing its arms. 

 These arms are bent in a circle round the head, 

 and in the same plane, just as if we should 

 clasp our hands a little above our foreheads. 

 The sucker, also, is placed in front. Hence 

 the parasite lies with its whole body close to 

 whatever part of the fish it may happen to fix 

 upon, and is like a scale or small protuber- 

 ance within its mouth. Still there would be 

 a danger of the parasite being displaced by 

 the violent gesticulations of the fish, or car- 

 ried down with the food which it gorges. To 

 prevent this catastrophe, and to keep itself as 

 comfortable as possible, it throws out or 

 raises a quantity of saliva, by which its back 

 is well lubricated ; so that the perch's food 

 passes over the flat and slippery surface, 

 without inflicting any injury by the tempo- 

 rary pressure. 



We suppose that this little creature never 

 sleeps, or else it possesses the power of holding 

 on during its slumbers. Its whole^occupa- 

 tion and enjoyment consist of sucking, a 

 work which must be continued when once 



Vol. HI.— 7. 



