20 



of an hereditai'}' disposition canuot be disputed, but at present we 

 know nothing oftliis in cattle.*^ 



It may appear in time that certain families are especially recep- 

 tive, but cases thus far studied can be just as well explained by the 

 more or less favorable opportunity for infection. There is at least 

 no reason to assume that a calf whose father or mother suffers from 

 accidentally acquired tuberculosis has there])y acquired an increased 

 disposiliou for the reception of tuberculous bacilli or offers a more 

 favorable nutritive soil for the multiplication of them. Finally the 

 disposition may be ever so great, but it can play no practical part if 

 we are in condition to avoid infection. 

 " We are sntHciently acquainted with the danger of infection when 

 healthy and sick live together. This is generally in the stable, more 

 rarely in the pasture, and is accomplished in various ways, by 

 infected air, water, fodder, etc. I wish to call attention particularly 

 to the probably still greater danger from feeding milk to calves. 

 Althougii the milk of the majority of tuberculous cows is fortunately 

 not dangerous, still among a large number of tuberculous animals 

 there would be some either with tuberculous udders or so advanced 

 in the disease that their milk, even without visible disease of the 

 udder would be infectious. ■^•' There is therefore the possibility in 

 many infected herds, that the calves may be infected bv feeding raw 

 milk. Of course other animals, as pigs, horses, etc., are subject to 

 like danger. 



Proof that this very often happens is shown by exi)erience 

 -obtained in Denmark as to the location of tuberculous infection of 

 calves which had been killed after a tuberculin reaction. Three 

 years ago I was able to mention in a Danish repoi't^*^ that among 35 

 dissections of such calves, 24 cases of tuberculosis, evidently from 

 feeding, were found. By this I mean tuberculosis was found either 

 alone or in its oldest form in the retro-pharyngeal or mesenteric 

 lymph glands and occasionally also in the intestinal wall. The numer- 

 ous dissections which I have made since then or which have been 

 sent me bv veterinarians have given similar results. As these calves 



4S. At ThurebyliUe the herd consists of several different families which all 

 belong to the red Danish race. 1 have investigated as to whether a difference in 

 the frequency or in the virulency of tuberculosis dependent upon family iliffer- 

 ences might be detected, but thus far without result. 



49. I have tested the milk of (53 cows in advanced tuberculosis. This has been 

 done by intra-peritoneal inoculation of guinea pigs and rabbits. I found 9 cases, 

 i. e., 14 per cent, to be virulent— Rep. of the Nat. Hygienic Congress, London 



:1891, Vol. 1 1 . p. I'.t.i. Und "Word. Med. Arkiv. Bd. XXllI. Nr. '25. 



50. Ugeskrift for Landmiind 1S9'2. 



