NATURAL HISTORY OF THE OX. 13 



sum of iJ100,000,000 sterling representing the totnl value of the 

 cattle of these islands. Mr. Youatt estimated the annual loss 

 to the country resulting from disease among cattle and sheep to 

 be about ^610,000,000 sterling ; but this sum is probably con- 

 siderably less than the actual amount. To this we have to add 

 that disease is a still greater source of loss in our colonies, 

 and hence there will be no diflBculty in coming to the conclusion 

 that the chief subject we are concerned with in the pages which 

 follow is one of the very highest moment. A most tran- 

 scendeutly important aspect of the diseases of animals is fur- 

 nished by the consideration that not only are many of these 

 maladies both preventible and curable, but also that some, at 

 least, of them, if not arrested, are indubitably capable of being 

 transmitted to human beings themselves. 



One of the points which comes up before us is the decision 

 of the place which the ox occupies in the scale of animate exist- 

 ence. Upon inquiry, then, we learn that this animal possesses 

 a vertebral column, and is therefore classed among the verte- 

 brata ; that it belongs to the large and important class of the 

 vertebrata known under the name of the mammalia, animals so 

 called on account of the fact that the females possess mammary 

 glands, or mammae, wherewith they suckle their young. Now 

 this class, the mammalia, is sub-divided into three groups, 

 respectively designated the Monodelphia, the Didelphia, and the 

 Ornithodelphia. It is to the first of these, namely to the Mono- 

 delphia, that the ox belongs, and, in passing, we may mention 

 that this group, which is sometimes also called the Placentalia, 

 comprises the greater number of the mammalia. The young of 

 the animals which compose this group are, while still within the 

 uterus, nourished by means of an organ, the allantois, a villous 

 and vascular development which grows out from the foetus. The 

 vessels of this organ come into close relationship with the blood- 

 vessels of the uterus, thus forming the placenta, and it is by this 

 method that an interchange takes place between the blood of 

 the mother and that of the foetus. This results in an absorption 

 of nutritive materials by the foetus and at the same time in the 

 removal of some noxious products from the blood of the foetus. 

 In fact, the allantois comes into contiguity with corresponding 

 vascular developments projecting from the inner wall of the 

 uterus, and the interchange spoken of thus takes place 



