686 EXPERIMENT STATION RECORD. [Vol.41 



" As Smith has pointed out, this infection furnishes a remarkable example of 

 the production of extensive destruction of the tissues of the host through 

 pressure exerted by a rapidly growing parasite. 



" Supplementing the presence of morphological characteristics not seen in any 

 of the amoebae, the daily feeding of Chaparro amargosa, a drug having definite 

 amoebical properties, has failed to prevent infection in young turkeys when 

 exposed to infected birds. 



" While the parasite shows a type of nuclear division similar to that of 

 trichomonads and an extranuclear body resembling a blepharoplast, various 

 other features characteristic of trichomonads have not been demonstrated. No 

 intermediate forms connecting this parasite with the trichomonads associated 

 with it in the caeca have been observed." 



A bibliography of 99 titles is included. 



EUEAL EKCtIITEEEING. 



The drainage movement in the United States, S. H. McCrory (17. S. Dept. 

 Agr. Yearbook 1918, pp. 131/-1U, pis. 6). — It is stated that there are approxi- 

 mately 102,800,000 acres of s^vamp, overflowed, and tidal marsh land In the 

 United States, of which about three-fourths are timbered. The author dis- 

 cusses the general features of drainage on a large scale, and emphasizes the 

 importance of collective action in such matters. 



Rainfall, absoi-ption, and run-off on small rural drainag'e area, I. E. HoUK 

 (Engin. Neivs-Rec, 82 (1919), No. 18, pp. 875, 876).— Observations of rainfall, 

 run-off, and soil absorption on a farm in the Miami (Fla.) Conservancy Dis- 

 trict are reported. The soil is clay loam containing some sand and gravel, and 

 is underlain by comparatively thick glacial deposits of sand and gravel. About 

 7 per cent of the surface is wooded, and the natural slope varies from 1 to 20 

 per cent. 



From a 24-hour rainfall of 3.51 in. an average increase in moisture content 

 in the soil of about 5.7 per cent was found. Run-off measurements indicated 

 that no run-off occurred on plats with sod covering. Considerable run-off oc- 

 curred on cultivated plats, varying from 37 to 44 per cent of the rainfall and 

 depending probably on the extent of cultivation. 



Run-off measurements from the total drainage area taken after this storm 

 showed an average maximum rate of run-off of 900 sec. ft., or 346 sec. ft. per 

 square mile, which is equivalent to a run-off rate of about 0.54 in. per hour. 



A hydraulic jump of about 2 ft. occurred abruptly at the lower end of a 

 concrete-lined channel where the water entered the earth channel, this rise 

 taking place within a length of 50 ft. 



Progress report on run-off investigations on Third Creek, Iredell County, 

 H. M. Lynde (North Carolina Sta. Rpt. 1918, pp. 74-87, figs. 5).— This report is 

 based upon investigations by the station and the U. S. Department of Agriculture, 

 covering five years and nine months, and conducted on a dredged canal through 

 Third Creek Valley for the purpose of determining the relation existing between 

 rainfall and run-off from drainage districts in the Piedmont section of the 

 Southern States. The water shed area is from 2 to 5 miles long, with an 

 average width of about 4 miles. The surface is rolling from the bottom lands, 

 terminating in narrow, flat uplands. The valley has a fall of 6 to 7 ft. per 

 mile at the lower end and about 15 ft. per mile at the upper end. The bottom- 

 land soils are sandy and silty loams, and the upland soils are clay and sandy 

 loams. The conclusion drawn is that for rainfall, topographic, and other condi- 



