Ixiv Trails. Acad. Sci. of St. Louis. 



Dr. Amand Ravold gave a microscopic demonstration of 

 Widal's test for typhoid fever, demonstrating that after the 

 disease has existed for four days or more, the blood of typhoid 

 patients, probably because of some contained antitoxine, pos- 

 sesses the power of inhibiting the motion and causing a 

 peculiar clumping of typhoid bacilli from a pure culture in- 

 troduced into it, within a period of one hour or less, whereas, 

 in normal blood, similar bacilli retain their power of loco- 

 motion for an indefinite length of time. It was stated that 

 typhoid blood possesses this property even after having been 

 dried for a period of four weeks or more, so that a few drops 

 obtained from a person suspected of having the disease may 

 be sent to suitable places for applying the test, thus rendering 

 comparatively easy the early diagnosis of a disease which in 

 its early stages presents many clinical difficulties. 



Professor F. E. Nipher gave preliminary results of partially 

 completed experiments, made through the courtesy of the 

 Burlington and Illinois Central Railroads, to determine the 

 frictional effect of trains of cars on the air near them. His 

 apparatus consists of a cup collector supported on a bar cap- 

 able of sliding in guides on a clamp attached to the window 

 sill of the car. The bar is thrust out to varying distances up 

 to thirty inches. The mouth of the collector is turned in the 

 direction of motion of the train. The pressure due to the 

 motion is conveyed through a rubber tube attached to the rear 

 of the collector and passing lengthwise through the bar to a 

 water manometer. The manometer has a tube with a rise of 

 four or five in one hundred, and is provided with a pivotal 

 mounting and a level. The pressure near the train is compa- 

 ratively small, and increases as the collector is thrust further 

 out, where it approaches a limit corresponding to the train 

 velocity at the instant. Professor Nipher finds the relation 

 between the limiting pressure and velocity to agree exactly 

 with the formula — 



where v is the train velocity in centimeters per second, P is 

 the pressure in dynes to the square centimeter, and 8 is 



