RURAL ENGINEERING. 687 



The transmission of swamp fever in horses, L. D. Swingle {Wyoming St a. 

 Rpt. 1013, pp. 93-123, ftr/s. 26). — The nutbor's feeding experiments with urine 

 and blood of infected animals show that it is not an easy matter to infect the 

 horse through the digestive tract, but do not prove that it is impossible to do so. 

 It is pointed out, however, that the amounts of blood and urine used in the 

 experiments and those used by other investigators who claim to have secured 

 infection by such methods are very large as compared with the amount that a 

 horse could possibly obtain under natural conditions. "Therefore, we may con- 

 clude that ingestion of blood or urine is not the natural mode of transmission 

 of the disease and especially would fail to explain efiidemics." 



Healthy horses which associated with sick ones for about 2 years, running 

 together in the same yard, feeding from the same mangers, and drinking from 

 the same trough, no precaution being taken against transmission, did not con- 

 tract the disease. In addition these animals drank water and ate grain and 

 hay contaminated with urine and blood from various infected horses, but not a 

 single case of infection resulted, except when directly inoculated hypoderrai- 

 cally or intravenously with virulent blood. 



In studies made of the blood of all the horses afterwards used in the experi- 

 ments bodies corresponding to the description and figures presented by Mack 

 in the account previously noted (E. S. R., 27, p. 684) were found, and in 

 some cases stained with Giemsa's stain rings similar to those described by Mack 

 were detected. The author states that it is almost certain, however, that the 

 rings in his slides are artifacts, there being all gradations between the small 

 rings, which are doubtful when considered by themselves, and large rings that 

 are unquestionably artifacts. These structures are said to have been found both 

 within or on the corpuscles and in the plasma. The author considers it pos- 

 sible that these bodies are a nonpathogenic Ana plasma such as is sometimes 

 found in healthy rats, goats, calves, pigs, and marsupials. 



The influence of compensated salt mixtures on the development of poly- 

 neuritis gallinarum and beri-beri, R. B. Gibson {PJiilippine Jour. Set., Sect. 

 B, 8 {1913), No. 5, pp. 351-367, pis. 4).— "The addition of a compensated salt 

 mixture to white rice fed to fowls has not prevented the development of poly- 

 neuritis gallinarum. However, the onset of the disease seems to have been 

 slightly protracted, and the degenerative changes in the nerves were less 

 pronounced." 



Reliable poultry remedies {Quincy, III., 1913, pp. 95). — This is a compilation 

 from the writings of several authors, including P. T. Wood and N. W. Sanborn. 



ETJRAL ENGINEERIIJG. 



Increasing the duty of water, B. A. Etche^'errt {California Sta. Circ. 114 

 (1914), pp. 8). — This circular summarizes available data, and points out that 

 for an average irrigation system the conveyance losses may be fully 30 per cent 

 of the water diverted, while of the amount delivered 25 per cent or more 

 may be lost by deep percolation, 25 per cent by soil evaporation, and 10 per 

 cent by surface run-off ; the total of these losses being 76 per cent of the water 

 diverted. 



" By adopting means of conservation which have been used successfully in 

 irrigated districts where water is valuable the waste and loss may be so 

 decreased that the water supply will serve two or three times the area served 

 with the irrigation methods now prevailing in many sections." '* Where the 

 value of the water will justify it, concrete linings will decrease the conveyance 

 loss to about 5 per cent of the water diverted ; the deep percolation loss, where 

 water is used with care, could be very nearly entirely prevented, and would 

 41074°— No. 7—14 7 



