Dec. 23, 1881.] 



♦ KNOWLEDGE 



155 



half a mile from the village of Mojo, and then had a breadth 

 of 23 ft and a height of 32 ft When the lava stieani was 

 e.-caniined near its source by the spectroscope, it showed the 

 lines of hydrogen, calcium, sodium, and potassium. Sil- 

 vestri has embodied liis observations in a monogi-aph ; 

 he has also just finished an important work, illustrated by 

 photographs showing various pluxses of eruption of Etna. 

 The work will no doubt be in print before the end of this 

 year. 



From Sicily, we pass at one stride to that country of 

 which the Danes say : " God made the rest of the world ; 

 the devil made Iceland." A few months prior to the 

 outburst of Etna, Hecla, which had not been in eruption 

 since 1845, showed signs of disturbance, and threw up a 

 Jiillock about four miles to the X.E. of the Great Crater. 

 A large quantity of very piuniceous lava was emitted, and, 

 at the time when tlie writer visited it, gi'eat quantities of 

 hydrochloric acid were discharged from crevices in the 

 lava, but the eruption was otherwise unimportant. 



Since 1872, Vesuvius has been only active at intervals. 

 Palmieri has published a full account of the 1872 eruption, 

 and in annual reports has given the history of the mountain 

 since that date. The eruption of Santorin, which began in 

 January, 186G, and lasted tUl October, 1870, has furnislied 

 results of great interest to vulcanologists, and it has led to 

 the publication of M. Fouque's magnificent " Santorin et 

 ses Eruptions," in which the whole history of the volcanic 

 phenomena and the products is given. The mineralogical 

 results have been of especial interest. Also we may note 

 the peeuliarit)' that, in the most violent period of acti\ity, 

 inflammable gaseous exhalations, which took fire on coming 

 into contact with red-hot lava, were emitted. The flames, 

 when examined by the spectroscojie, were found to consist 

 of hydrogen, containing small quantities of copper, sodium, 

 and clilorine. As the gaseous emanations of Santorin are 

 emitted inider water, they are not burned at the point of 

 issue, and can lience be examined readily. As much as .56 

 per cent, of hydrogen was found in some of the exhalations, 

 and the author concludes, we think without suflicieut war- 

 rant, that the enormous quantities of water-vapour emitted 

 in volcanic eruptions exist in the red-hot magnia of lava, 

 not as water, but as dissociated hydrogen and oxygen. 



The record of recent earthquakes will be fresh in the 

 minds of our readers. Tliree calamitous earthquakes 

 have occurred witliiii the last eight months — at Ischia, in 

 Chios, and at Agram. In the latter 4,000 persons 

 perished, double that number were maimed, and 30,000 were 

 rendered homeless. It commenced on April 3, but several 

 months aftenvards a minaret and a tottering wall were over- 

 thrown, and in all there were at least 2-50 shocks. In 

 1870, a great earthquake occurred in Phocis, north of the 

 Gulf of Corinth. Professor Julius Schmidt, the Greek 

 Astronomer Eoj'al, has gi\en a detailed account of it. 

 It is asserted that during the first three days a shock 

 was felt every third minute, while Schmidt himself 

 counted nearly 2,000 in the twenty-four hours, four 

 days after the great outbreak. Altogether, during 

 five months of 1870, it is calculated that the shocks 

 and detonations exceeded half-a-million. In October, 

 1870, the most severe shock of earthquake observed during 

 the present century in the north-eastern states of North 

 America was felt at Quebec. It was instantly telegraphed 

 to Montreal, and tlie message arrived nearly half a 

 minute before the shock. The Peruvian earthquake 

 of Aug. 13, 1868, was felt the same evening in Hawaii, 

 6,300 miles distant 



We are as far as ever from the knowledge of the cause of 

 earthquakes, but, undoubtedly, high pressure steam has 

 much to do with it The author of the article-, " Earth- 



quakes," in the July Quarterly Review, propounds a 

 theory- to the ettect that electricity is the true cause, but in 

 what manner he has not clearly defined. We do not consider 

 that his arguments will bear criticism. Hero is one of 

 them : — " The vicinity of hot springs, volcanoes, mud lakes, 

 regions of intense heat, and centres of electric influence, 

 are the special haunts of earthquakes, and science has 

 pretty well proved that heat and electricity are conver- 

 tible.' * One word in conclusion as to volcanic products. 

 But few new minerals have lately been found. Professor 

 Scacchi announced two years ago the discovery of a new 

 element, which lie termed vesbium, among the lavas of 

 Vesuvius, but we have not heard that it has ever been 

 isolated. The most remarkable volcanic product lately dis- 

 covered is undoubtedly a substance from the crater of 

 Volcano, analysed by Professor Cossa, of Turin. It was 

 found to contain seven non-metals and eight metals, among 

 the latter the rare and recently-discovered elements, caesium, 

 rubidium, and thallium. 



OUR UNBIDDEN GUESTS. 



By Dr. Andrew Wilson, F.R.S.E. 



IT is much the same with the tapeworm-tribe as with the 

 fluke (considered in Part I.) The common tapeworm 

 of man [Tcnnia Solium) consists of a very minute " head," 

 attaching itself bv suckers and hooks to man's intestines ; 

 of a slender " neck," and of hundreds of "joints." Each 

 "joint " is really a semi-independent animal ; and the tape- 

 worm is therefore a coinpoimd animal, and presents us with 

 a colony of similar beings. A large tapeworm may measure 

 20 or 30 ft. ; and new joints are continually being " budded " 

 out from the head and nock. Hence the physican can never 

 be sure that he has cured a case of tapeworm until he has 

 seen the head and neck of the animal If a man swallowed 

 the egg of a tapeworm, he would not be infested thereby. 

 The young worm has to pass its early life in the body of 

 another wann-blooded animal ; and in the case of the 

 common tapewoiin, it is " the gintlenian that pays 

 the rint," wliich acts the part of nurse or first host. 

 Man, in other words, obtains his common tapeworm 

 guest from the pig. When this animal swallows the 

 egg of a tapeworm, the young worm bursts through the 

 egg-case and bores its way to the pigs muscles. If the 

 porker is aff'ected by numerous embryos, tliat is, if it has 

 swallowed a large number of eggs, it will become feverish 

 and ill, and it • will then be said to have developed 

 "measles." The " measles " of the pig are the visitations 

 of young tapewomis. In the muscles of the pig, then, 

 these young worms rest. Je suis ici ; f;/ reste, is decidedly 

 the motto of the young wonn. It developes a little head 

 and neck, and it also, by way of a tail, produces a little 

 bladder or bag. Before naturalists knew its true nature, 

 it was regarded as a special kind of parasite, and was 

 named a " cystic worm. " 



If the pig dies a natural death and is respectably in- 

 terred, or if the pig should live long enough, these 

 youthful tapeworms will respectively perish, or will dege- 

 nerate and disappear from the tissues of the aged porker. 

 But assuming that the usual Kemesis of the pig race over- 

 takes the animal, then, in the form of pork, it will gladden 

 the heart of certain members of the human race. Now, 

 let us suppose that a man eats a portion of the " measly 

 pork." Let us further suppose that the pork has been 



* The article is utterly without ecientilic value. How it found 

 ts way into a magazine of good position is a mystery. — Ed, 



