(3 PREFACE. 



Accompanying these reports are two series of micro-photographs of 

 great beauty and value, which are not roprortuced here. One is a series 

 of eight niicro-photographs, i)ainted, illustrative of diseased organs and 

 tissues of cattle laboring under pleuro-pneunionia. The second series is 

 a group of twelve micro-photographs of diseased tissues and organs of 

 cattle that have died of the Texas fever or of pleuro-pneumonia, which 

 latter series has been taken at the Army Medical Museum in this city, 

 under the supervision of Brevet Lieutenant Colonel J. J. Woodward, 

 United States army, from specimens of disease forwarded from various 

 points. An exi)lanatory report of the pathological indications, from the 

 pen of Dr. AYoodward, accompanies the plates, and it is to me a matter 

 of great regret that these portions of the work done for the Department 

 cannot appear with the reports in the present edition. The cost of repro- 

 ducing these as illustrations is so great that I have not felt authorized 

 to expend the Department appropriation in order that they might be 

 inserted here. As, however, they are essential parts of the report, and 

 necessary to complete the medical natural history of the diseases treated 

 of, it is hoped that a sum sufficient to cover the expense of engraving 

 will be appropriated by Congress, so that in another edition they may 

 be added, and the reports appear in complete form. 



The rapid extension of pleiu'o-pneumonia during the summer of 18G8, 

 and its increased fatality at points where cattle were collected in num- 

 bers, made it the duty of the Department to ascertain its nature, extent, 

 and the possible means of checking or wholly obliterating it. 1 there- 

 fore authorized Professor Gamgee, in the autumn of 1868, to make a full 

 investigation of the disease then spreading through many States of the 

 Union. In December of that year Professor Gamgee presented a prelim- 

 nary report, which was published in the monthly reports of 1808. His 

 final report is herewith presejited. 



HOEACE CAPEOX, 



Commissioner of Agriculture. 



