258 STATE BOARD OF AGRICULTURK. 



show that the incdinni bocnme toxic to bartoria at (lifTcT'cnt iiines de- 

 pending; upon the salt present. 



All this work and that of the effect of the micro-organisms npou 

 various fertilizers in soil will be taken up in detail in a x>wblication 

 in the near future. 



About a year ago with your consent, the writer in co-operation with 

 Mr. W. S. Robbins, at that time connected with this department in the 

 manufacture of hog cholera serum, now with the Pathological depart- 

 ment, took up the study of the growth of the hog cholera virus in the 

 soil solution as a j)reliminary to the study of soils infected with said 

 virus. Some progress has been made in the work thus planned. The 

 work has been delayed somewhat for lack of material. 



At the meeting of the American Bacteriologists, held at Urbana, 

 Illinois, December 28-30, 1915, the writer presented a paper entitled 

 "The Soil Solution as an Index of the Biological Changes in the Soil" 

 and in conjunction with Mr. Gruzit, "Reaction of the Soil Solution as 

 an Index of the Biological Changes in the Soil." Abstracts of both 

 papers appeared in the first number of the "Journal of Bacteriology." 

 Mr. Gruzit presented a paper on "The Effect of Natural and Modified 

 Soil Solution on Bacteria" at the meeting of the Sanitary Section of the 

 Michigan Academy of Science held at Ann Arbor, March 29, 1916. (J. 

 Frank Morgan.) 



Mr. L. C. Ludlum came to us in September, 1915, from the University 

 of Michigan, to take up the work in hog cholera research suspended in 

 March of the same year by the resignation of Dr. L. R. Himmelberger. 

 These breaks in the continuity of research problems are unfortunate, 

 creating, in many instances, delay's in the progress of the work due to 

 the necessity of breaking in new men, that are far more expensive than 

 the increment in salary essential to the retention of a good man already 

 familiar with the project. We are pleased with the manner in which 

 Mr. Ludlum has taken up his duties. His report follows: 



^'Mj work has been almost entirely in the field of pathogenic bacter- 

 iology, with some aspects of hog cholera as the main problem. The 

 first three months were largely spent in reviewing the literature of hog 

 cholera. 



The research work on hog cholera has been pursued with four definite 

 ideas in view, viz.: 



First: Cultivation Experiments. The artificial cultivation of the 

 filterable virus of hog cholera has' never been accomplished. Success 

 in this attempt would open the way to much valuable work in this and 

 related fields. 



Filtered virus blood and filtered virus salt solution will be used in 

 media of various kinds. The methods of Noguchi, successful in the 

 artificial cultivation of certain anaerobic, filterable organisms, will be 

 carried out. 



Second : Development of an early and accurate laboratory diagnostic 

 method for hog cholera. 



The isolation or extraction of the specific casual agent of hog cholera 

 would give us an antigen which might prove of value in agglutination 

 and complement fi'xation tests with virus serum. 



Different extracts of various organs and tissues of vims hogs will be 

 tried out in the attempt to secure such an antigen. 



