186 EXPERIMENT STATION EECORD. 



organism coming from widely distributed sources were studied in the present 

 investigations. . . . 



" Tlie virulence of tlie cultures studied was characterized by great variation. 

 The range of the minimum lethal dose of a 48-hour bouillon culture was for 

 fowls from 10 cc. to 0.000,000,000,000,001 cc, and for rabbits, from 10 cc. to 

 0.000,090,000,000,000,000,01 cc." 



It was also noted that " infection resulted from the inoculation into the 

 breast muscle of less than 50 organisms, and probably by the inoculation of no 

 more than 4. [This] suggests an immediate paralysis of the phagocytic func- 

 tion in infected birds, and offers an explanation for the great iufectivity of the 

 disease among poultry under natural conditions." 



The cultural investigations of this cholera organism indicate that : " ( a ) The 

 cause of fowl cholera, as encountered, is not a polymorphic organism in the 

 same sense that B. diphtherice is a polymorphic organism, (b) There is no 

 good ground, in the case of the cultures studied, to separate a group of pseudo- 

 cholera organisms, on the basis of mox'phology, virulence, or any cultural fea- 

 ture; all belong in one large group in which there is great variability with 

 regard to these 3, as well as many other, points, (c) There appear to exist 

 correlations between virulence and certain cultural features, such as indol- 

 production, acid-formation, nitrate reduction, etc. But this point should be 

 further established by the study of a great number of cultures, (d) In view 

 of the points brought out in (a) and (b) above, the presence of any organism 

 manifesting the type features of the cholera group, notwithstanding the absence 

 of pathogenesis, should be regarded with suspicion, (e) The slight resistance 

 of the virulent cholera cultures to carbolic acid, and to all acid media or solu- 

 tions tried, offers a suggestion as to therapeutic possibilities. Studies involving 

 this feature are now in progress. 



" Immunological studies, so far as they have been extended up to the present 

 date, indicate that a highly Airulent culture encounters resistance in a sus- 

 ceptible animal when this animal has been previously inoculated with an 

 avirulent, homologous culture; resistance, in rabbits, to 10,000,000,000 times 

 the minimum lethal dose of a very virulent culture has been artificially pro- 

 duced by a single large dose (3 cc.) of the homologous culture. None other 

 than homologous cultures produced such resistance in rabbits." 



" The resistance of the cholera organisms to heat, drying, carbolic acid and 

 hydrochloric acid was also tested." 



Further studies on blackhead in turkeys, P. B. Hadlet and Elizabeth E. 

 Amison (CentU. BaM. [etc.'], 1. AU., Orig., 58 {1911), No. 1, pp. S-i-Jfl).— The 

 authors state that during the course of investigations conducted in continuation 

 of those previously noted (E. S. R., 24, p. 187), cases of cecal and liver infec- 

 tion in which coccidia appeared to be absent or present only in small numbers 

 have come under observation. In these instances flagellated organisms were 

 frequently present in the intestinal and cecal content in great numbers. The 

 results of examinations made of cecal contents and of sections are described 

 and the possible agency of flagellates in producing hepatic and intestinal lesions 

 that are characteristic of blackhead briefly discussed. 



They conclude that " the data presented in this paper offer reliable grounds 

 for the opinion that many cases of blackhead in turkeys and other poultry 

 may be interpreted as infections with one or more species of flagellated 

 organisms. These may be identical with the flagellates observed by Theobald 

 Smith in the ceca of turkeys ; they are undoubtedly identical with some of 

 the other bodies described by Smith under the name of Amoeba meleagridis. 

 . . . The course of development probably does not depart widely from that 

 of certain other parasitic flagellates which have the habit of losing their flagella 

 and becoming ameboid at certain stages in their development." 



