1919] VETERINARY MEDICINE. 685 



" The organism Is agglutinated by immune serum for the organisms of para- 

 typhoid-enterltidis group in fairly high dilutions. Serum of rabbits immune to 

 this organism also agglutinate B. suipestifer, B. enteritidis, and B. paratypho- 

 sus A and B in dilutions high enough to indicate a close serologic relationship 

 to these organisms." 



Strong'ylidae in horses, W. Yobke and J. W. S. Macfib {Ann. Trop. Med. and 

 Parasitol., IS {1919), Nos. 1, pp. 51-62). — In continuation of previous papers 

 (E. S. R., 41, p. 87), the authors describe a seventh new species to vehich the 

 name Cylicostomum pateratum is given. 



Strong'ylidae in horses. — Species found in American horses, W. Yorke and 

 J. W. S. Macfie {Ann. Trop. Med. and Parasitol, 13 {1919), No. 2, pp. 1S7-U3, 

 pis. S). — In continuation of the paper above noted, the authors list the species 

 of StrongylldJE found in 15 horses from the United States examined in England, 

 of which 8 belong to the genus Strongylus, 8 to Trlodontophorus, 2 to Gyalo- 

 cephalus, and 12 to Cylicostomum. This is followed by a complete list of all the 

 Strongylinse In horses, donkeys, and mules recorded from different parts of the 

 world. The pathological findings and their pathogenicity are briefly considered. 



On the transmission of two fowl tapeworms, J. E. Ackert {Anat. Rec, 15 

 {1919), No. 6, p. S41; abs. in Jour. Roy. Micros. Soo., No. 1 {1919), p. 7/3).— In 

 investigations at the Kansas Experiment Station, the author has found that the 

 house fly may transmit to chickens two tapeworms, one which appears to be 

 Davainea tetragona, the other D. cesticillus. Files were trapped in poultry 

 yards where chickens were known to be Infested and were fed to 17 isolated 

 chickens. Two of 4 chickens examined were found to be parasititized by D. 

 tetragona. In similar experiments in 1917, D. cesticilhts was transmitted to 

 chickens (E. S. R., 40, p. 359). 



Developmental phases of the protozoon of " blackhead " in turkeys, E. B. 

 Tyzzer {Jour. Med. Research, 40 {1919), No. 1, pp. SO, pis. 2). — "The parasite 

 Amoeba meleagridis presents a variety of forms which it would be difficult to 

 identify except for the constant presence of an extranuclear body. From this 

 are derived the division centers and a well developed paradesmose which may 

 stretch from side to side of the dividing cell. Binary nuclear division of a 

 character similar to that described In trichomonads is encountered frequently. 

 No indication of any process of multiplication other than binary division has 

 been f»und. 



" Motility, as observed in the warm chamber, is of the nature of amoeboid 

 motion of a slow rate. A large proportion of the organisms examined show no 

 motion. 



" The various forms assumed by the parasite and their relationship to the 

 pathological process indicate distinct phases of development. In the invasive 

 phase, the parasite may ingest solid particles as food, and migrates freely 

 through the tissues. The vegetative phase is characterized by the loss of 

 motility and by the absorption of fluid in the place of ingesting solid material. 

 The cytoplasm in both these phases is distinctly basophilic. The resistant 

 phase is characterized by its small size, acidophilic cytoplasm, and by encystment. 



" Multiplication by binary division is most active in the invasive phase, 

 continues in the vegetative phase, and ceases in the resistant phase. 



"Contrary to Hadley's claim (E. S. R., 86, p. 781), A. meleagridis should not 

 be regarded as a cell parasite. Although it migrates freely through the tissues. 

 It does not occur within cells except after motility is lost, when it is soon 

 phagocyted. Within cells the reaction of the organism Is purely defensive; 

 multiplication ceases, it decreases in size, and develops a resistant membrane. 



