24 



NATURE 



[3fajy 9, 1872 



OUR BOOK SHELF 



Worms ; a Series of Lectures on Practical Helminthology, 

 delivered at the Middlesex Hospital, by T. Spencer 

 Cobbold, M.D., F.R.S. (London : Churchill, 1872.) 

 Thf.se lectures do not pretend to give any very minute 

 anatomical details, or any full account of the lifo history 

 of the remarkable group of animals of which they treat, 

 and which Dr. Cobbold has so long and so carefully in- 

 vestigated. They were originally delivered to medical 

 students, but are so simply and clearly written that they 

 might advantageously ba read by the public. They show 

 the frequency with which parasites occur in man, and the 

 necessity of careful supervision of the animal food ex- 

 posed in our markets for sale, especially at night and to 

 the poor. Dr. Cobbold remarks that the terms " measly 

 mutton " and " measly beef" are terms which will sound 

 strange to those who know of no other " measled meat " 

 than porl< ; but he points out that his investigations have in- 

 contestably proved and verified the existence of larval 

 tapeworms in the most esteemed kinds of animal food. 

 The tapeworms derived from these three kinds of meat, 

 beef, mutton, and pork, though agreeing in their general 

 characteristics, yet differ in minor points, and especially 

 in the shape of their heads. The head of the beef tape- 

 worm is destitute of hool-cs, anu has four large suckers, 

 besides a supplementary fifth (so called) ; whilst the head 

 of the pork tapeworm is a trifle smaller, and furnished 

 with a slightly prominent proboscis, armed with a double 

 ro.v of hooks. The mutton tapeworm is also armeil, 

 at least the "measle" is provided with hooks. A 

 fully-developed beef tapeworm numbers about eleven 

 hundred joints, and attains its full development in abjut 

 thirteen week? or rather less. Dr. Cobbold appears to 

 regard the well-made ethereal extract of the root of male 

 fern as by far the best remedy for tapeworm, though 

 kousso, kamala, turpentine, panna, pumpkin seeds, betel 

 nuts, and the bark of the pomegranate, are occasionally 

 successful in effecting their expulsion, and will some- 

 times accomplish this when the oil of male fern has 

 failed. In regard to thread worms [Oxyiiris iicnnicularis) 

 Dr. Cobbold states that it is quite a mistake to suppose 

 the lower bowel or rectum forms their special habitat. lie 

 recommends santorine, with active saline purgatives, and 

 copious enemata, for their removal. The large, round 

 worm, Ascaris lumbiicoides, and the Ascaris niystax, are 

 in his experience rare, the latter, indeed, very rare in 

 England, but they are endemic in some regions, as in the 

 Mauritius. The Trichina appears to have been only once 

 recognised and treated in the human subject, namely, by 

 Dr. Dickenson, of Worthington. In this instance Dr. 

 Cobbold calculated that the patient played the host to 

 forty million of the parasites. He observes that when 

 once the Trichina has gained admission to our muscles, all 

 hopes of dislodging it are at an end ; l^ut if a person sus- 

 pects that he has eaten diseased or trichinised meat, he 

 should lose no time in seeking assistance. Immediate 

 advice, followed by a suitable antitrichinalic, might be 

 the means of saving his life, whereas a few days' delay 

 would perhaps prove fatal. Whilst the worms are in the 

 intestinal canal we can get rid of them, but when once 

 the trichinal brood migrates into the fiesh no means are 

 known by which their expulsion can be cft'ected. The work 

 terminates with some amusing cases of spurious worms. 



H. P. 



LETTERS TO THE EDITOR 



[ The Editor does not hold himself responsible for opinions expressed 

 bv his correspondents. No notice is taken of anonymous 

 commnnications. ] 



Recent CUmatic Changes 

 Lv two previous letters I have tried to show that the land is 

 gaining on the sea at both poles ; in other words that the peri- 



phery of the earth is being thrust out in the direction of its shorter 

 axis. If this change has been so great as to make it probable 

 tliat tlic Classical and Arabic accounts were correct when they 

 made Scandinavia an archipelago in the earlier centuries of our 

 era, we may be sure that it has not been without material iafluence 

 upon other physical plienomen.!, and notably upon climate. 



One obvious result of the conversion of a great space of water 

 into an area of dry land in the high latitudes confined by the Arctic 

 and Antarctic circles, would be to alter very materially the mean 

 climate of both hemispheres. This has been noted by many 

 inquirers into the subject, and not least by Mr. Hopkins in his 

 very ingenious criticism of the different potential climatic revolu- 

 tions which are consistent with the presence or alwence of certain 

 elements like the one we are dealing with. Ingenious and most 

 interesting as Mr. Hopkins's well-known paper in the Geoloxieal 

 TraitSiictioiis is, it does not, I think, quite explain facts as 

 observed. I am not writing in emulatioi of one who has every 

 claim to be considered an authority, but in the humbler guise 

 of a student whom you are always willing to assist, who desires 

 some of your correspondents to throw hght on a difficult and 

 neglected question. 



The increase of land at the poles at the expense of the water 

 will tend to intensify the extremes of temperature in winter and 

 summer, and in consequence, to make the climate much less con- 

 stant and uniform and much more severe ; and we ought to find 

 evidence of this somewhere, if the premisses of my two previous 

 letters are tenable. I wish to adduce a few facts in the way of 

 sucli evidence, and to ask your correspondents for more either 

 pro or con. Many such must exist. 



Greenland is a name which seems ironical under present condi- 

 tions of climate. It has always seemed to me that the land there 

 has changed its appearance very considerably since that name was 

 applied to it. The Esquimaux were apparently not known as 

 inhabitants of Greenland to the S.aga writers. The skzcUings 

 they met with were on the coasts of Labrador and farther South. 

 They first appeared after the black plague had nearly destroyed 

 the Norse settlements, and they completed the work the pestilence 

 had commenced. They came from the north, probably from the 

 area now occupied by the so-called Arctic Highlanders. The 

 Indians who now live along the march, or frontier, bounding 

 them and the Esquimaux in S'orth America, have an apparently 

 uniform tradition, that the Esquimaux were formerly not neigh- 

 bours of theirs, and that they came south across the sea from the 

 islands beyond. I believe that I have sufficient facts by me to 

 justify the opinion that the Esquimaux of both shores of Ilehrings 

 Straits have been constantly drifting westwards and south ward.s, 

 and that they are but recent occupants of their present area there. 

 This wdl appear in a future communication to the Anthropologi- 

 cal Institute. These facts are quoted to show that the Esquimaux 

 race has been uniformly leaving its more northern habitat and 

 seeking a more southern one. It is remarkable that the recent 

 Swedish Expeditions to the Eastern Coasts of Greenland found 

 abundance of reindeer and musk-oxen there in areas formerly 

 uninhabited by both animals. This emigration must have come 

 from the north. I can see no adequate causi for a revolution 

 affecting men as well as other animals in such a uniform manner, 

 except the continuously increased severity of local climates which 

 has driven the inhabitants farther south. 



Iceland has notoriously become more harsh and untenable 

 in its climate since the days of the Norsemen. I will quote from 

 a capital authority, Henderson's Journal in Iceland, pages 6 and 

 7 : — "It is evident from ancient Icelandic documents that on the 

 arrival of the Norwegians, and for centuries afterwards, pretty 

 extensive forests grew in different parts of the island, and fur- 

 nished the inhabitants with wood both for domestic and nautical 

 purposes. Owing, however, to the improvident treatment of 

 them, and the increased severity of the eliniatej they have almost 

 entirely disappeared, and what remains scarcely deserves any other 

 name than that cf underwood, consisting for the most part of 

 birch, willow, and mountain ash. That grain was produced in 

 former times in Iceland appears from the names of many places, 

 such as akkrar, akkrances, akkraheron, &c., the word ahr signi- 

 fying a cornfield, and from certain laws in the ancient code, in 

 which express mention is made of such fields, and a number of 

 regulations arc prescribed relative to their division and cultiva- 

 tion." Grain is no longer raised there. The Black Heath, and 

 other reasons, have been adduced for this cessation ; but these are 

 clearly inadequate causes, the real reason being no doubt the 

 same which has caused grain culture to be discontinued elsewhere, 

 namely, the increased severity of the climate. 



