No. 6. DEPARTMENT OF AGRICULTURE. 129 



4. CHRONIC BACTERIAL DYSENTERY 



Having- had an opportunity to study this disease in Europe and 

 extra etjfort has been made to continue the investigation in this 

 country. Efforts were made to reproduce the disease in cattle. Tests 

 were carried out to determine the diagnostical value of Avian Tuber- 

 culin. Several animals kept under isolation supplied the necessary 

 material for this work. A cow purchased in Northampton count}- gave 

 only a slight positive ophthal mo-reaction to Avian tuberculin, but 

 proved to be affected with bacterial dysentery when autopsied. In 

 several cases post mortem and microscopical examinations confirmed 

 the reaction obtained with Avian tuberculin. The lesions found were 

 different than those described by Prof. Bang and previously observed 

 by the writer. Chronic intoxication and anemia were more pro- 

 nounced and the lesions in the intestinal tract are less prominent than 

 are usually seen in European cases. In three instances we succeeded, 

 by means of intra-venous inoculations of emulsions of tissues con- 

 taining the specific acid fast bacillus in large quantities, in repro- 

 ducing the disease in such a form that the animal would react to 

 avian tuberculin. Attempts to cultivate bacillus on at least thirty 

 different culture media failed entirely. Inoculations on guinea pigs 

 showed lesions similar to those produced by the inoculation of ma- 

 terial from pigeons which contained an acid fast bacillus very much 

 like those found in Bacterial Dysentery. 



5. CONTAGIOUS ABORTION 



The prevalency of this disease demanded thorough and urgent 

 investigation. In different instances pure culture of the Bang bacillus 

 was obtained from the intestinal tract of a foetus. The morphologi- 

 cal and biological characteristic of this bacillus will be published 

 later. Proof can be given to show that "Granular Vaginitis" of cows 

 is not responsible for contagious abortion. Preparations have been 

 made to install the complement fixation and agglutination test for 

 diagnosing this disease. 



6. HOG CHOLERA 



The preparation of serum for the immunization of hogs against 

 hog cholera involved a considerable amount of work. Under the con- 

 dition serum was prepared the year before the amount was not suffic- 

 ient to answer the requirements. Climatic conditions did not permit 

 an extensive serum production during the winter months, and it 

 was the idea of Dr. Leonard Pearson to construct a special building 

 for this particular work at the farm. The plans, based more or less 

 on his idea, were submitted by Mr. Hileman at the beginning of the 

 year to the Board and accepted. In the beginning of May the erection 

 of the building was started, but was not completed until the middle 

 of November. The entire building is of stone and concrete construc- 

 tion, with perfect drainage into a well in which the refuse and drain- 

 age of the hog cholera building as well as of the post mortem labora- 

 tory can be thoroughly disinfected. 



At first we had difficulties in obtaining the necessary amount of 

 virulent blood to be used for hyper-immunization purposes. Pre\ious 

 to October, 1911, such blood was collected from sick hogs in out- 

 breaks in the neighborhood of Philadelphia and inoculated into im- 



9—6—1911 



