THE FARMER'S MAGAZINE. 



467 



that send so many cattle to the dog-keunel and knacker'a 

 caldron. From a commercial point of view, the interest of the 

 public ought unquestionably to be the farmer's rule. And 

 even from a scieutific and ecouoraical point of view, the beat 

 quality of meat at table is the ouly solid foundation on which 

 to base the improving of our breeds of cattle; but to this we 

 shall return as the subject of another lucubration. Meantime 

 we shall only farther add, that as the hereditary tendency to 

 the diseases in question terminates, under a certain force of 



circumstances, in an extra weight of inferior quality of both 

 fat and lean, and also terminates, under a different force of cir- 

 cumstance, in what we shall here designate, for the sake of 

 brevity, poverty, or a deficiency of weight, it can hardly be 

 surprising that the fattening of cattle under such a system is 

 pronounced by so many to be a losing concern, and that the 

 times are growing worse than they were, even with all the 

 improvements we are making ! W. B. 



THE ROT IN SHEEP, AND THE VIEWS OF GERMAN NATURALISTS. 



So much has recently been said and written on the rot, 

 or bane, in sheep, that, were it not for the great import- 

 ance of the subject, and the absence of any authoritative 

 teaching by the professors at the lloyal Veterinary College, 

 any further discussion in these columns might be thought 

 inopportime. When, however, it is considered that the 

 loss entailed by this malady on the farmers of Great Britain 

 has been estimated to amount, in ordinary years, to no* 

 less than two-aud-a-half millions sterling, and that serious 

 doubts are entertained whether meat in any but a perfect 

 state of health and soundness can be eaten by man with 

 impunity, it will be admitted that anything which tends to 

 throw a light on this dark and perplexing problem is en- 

 titled to grave attention. Professor Simonds, it is satis- 

 factory to know, is engaged in a series of investigations) 

 while it may interest the agricultural public to be 

 infoiTued, as briefly as possible, of what has been already 

 ascertained by previous inquirers. 



The fluke, which infests the liver and biliary ducts 

 of sheep affected with rot, is known as the Distoma 

 Jiepaticum, and is an ento^ooii, or internal parasite, of 

 the trematodc (adhering by suckers) order. Professor 

 Owen, who has written very briefly on the form and cha- 

 racteristics of this species of entozoon, in " Todd's Cyclo- 

 poedia of Anatomy and Physiology," says that, in extremely 

 rare instances,it is foundin the gall-bladder and ducts of the 

 liver of the human subject ; and Dr. Lankester, in the Ap- 

 pendix to his Translation of KUchenmeister on " Animal and 

 Vegetable Parasites," mentions a case which occurred in 

 the practice of a country surgeon, where an undoubted 

 fluke was extracted from behind the ear of a sailor. Our 

 ohject in mentioning these isolated instances is not to ex. 

 cite alarm, or create an unnecessary digression, but simply 

 for the purpose of explaining how it happens that so little 

 has been done by English naturalists and pathologists 

 ■with a %iew to illustrate the particular points in which 

 the agricultural public are more especially interested. 



It is a well-known fact that Dr. Edward Jenner was led, 

 by his obseiTations on the aUmems of cattle, to draw those 

 important conclusions with refei'ence to the human sub- 

 ject which conducted to his gi-eat discovery of vaccination. 

 Since his time, however, the tendency of public opinion 

 in England has been to draw so strong a Une of demarcation 

 between the treatment of disease in man and the inferior 

 animals, that a great social gulf divides the two classes of 

 practitioners. The eftect of tliis absurd distinction has 

 been to deter aspiring minds from a branch of study 

 which, however important in itself, confers no proportion- 

 ate reward on those who piu'sue it. Hence it occurs that 

 the treatment of the diseases of cattle, notwithstanding all 

 the grave physiological questions which are frequently in- 



volved, has been remitted exclusively to the veterinai7 

 practitioner ; and, to use the emphatic language of Lord 

 Berners, on a recent occasion, " with all respect for the 

 veterinary art, it appears as yet to be only in its infancy." 

 In Germany, a totally difterent class of influences has pre- 

 vailed. With the march of impi'ovement in the micro- 

 scope, there has been a corresponding desu'e among 

 scientific men to explore the great mysteiy of animal or- 

 ganization in its lowest tj-pes ; and though, a few years 

 ago, a drawing-room doctor at the West End of London 

 would have recoiled from the imputation of passing his 

 time in the study of intestinal worms, the discoveries of 

 Steenstrup, the Danish naturalist, have not only invested 

 such inquiries with interest, but thrown a flood of light on 

 the hitherto-secret operations of Nature. 



As the reseaches of Steenstrup, and more especially his 

 remarkable work " On the Alternation of Generations,"* 

 have given an entirely new direction to the studies of 

 naturalists — teaching more especially that entozoa such as 

 the fluke only reach a perfect state of development after 

 passing through several stages, and that it is vain to look 

 for them in their perfectly-developed forms in any other 

 situations than the liver or other congenial organisms — 

 it may tend to strip the subject of a great deal of needless 

 mystery, if we briefly describe what is meant by this pro- 

 cess of metagenesis. For this purpose we cannot do better 

 than quote a few of the introductory remarks of Steen- 

 strup himself in reference to his very interesting dis. 

 covery : 



"By the words 'alternation of generations,' is meant, 

 the remarkable and tQl now inexplicable natural pheno' 

 menon of an animal producing an ofispring which at no 

 time resembles its parent, but which, on the other hand, 

 brings forth a progeny which returns in its form and 

 nature to the parent animal, so that the maternal animal 

 does not meet with its resemblance in its own brood, but 

 in its descendants of the second, third, or fourth degree 

 or generation, and this always takes place in the different 

 animals which exhibit the phenomenon in a determinate 

 generation, or with the intervention of a determinate num- 

 ber of generations. This remarkable precedence of one 

 or more generations, whose functions it is, as it were, to 

 prepare the way for the later, succeeding generations of 

 animals destined to attain a higher degree of perfection 

 and which are developed into the form of the mother, and 

 propagate the species by means of ova, can, I believe, be 

 demonstrated in not a few cases in the animal kingdom. 

 * * * * In the class entozoa raj researches have 

 suSiced to prove, not only the existence of such an alterna- 



* A translation of this work by Busk, was published, by the 

 Ray Society in 1845. 



