EXPlvRIMENTAL AND ANALYTICAL WORK 



15:^9 



The error due to the presence of chlorides persisted even when diges- 

 tion was carried on at a moderate temperature. This error was reduced, 

 although not eliminated, if digestion was carried out at or below room 

 temperature and if the final titration of excess potassium permanganate 

 was made with sodium thiosulphate in the presence of potassium iodide 

 and starch indicator. It was further reduced by digesting the water 

 samples with potassium permanganate in alkaline instead of acid solu- 

 tion according to the method described by Schulze, and Winkler (i). 



A last series of tests was undertaken to determine the effect, if any, 

 of the presence of traces of hypochlorite in the water. It was found that 

 h3^pochlorites oxidize organic matter in cold or hot solution and should 

 therefore be eliminated before any determination of the ox^'gen consu- 

 ming power is made. 



I'^rom these results it is evident that the determination of oxygen con- 

 sumption is not at best an accurate measure of the organic content of wa- 

 ter and it gives such uncertain results that isolated determinations are 

 of very little value. It is only when a water supply is to be consumed 

 repeatedly that the method becomes very useful. 



irGo - ImmLinUy to Cow Poxasja Result of Intravascular Infections. — camus l , in 



Comptcs Rendus dcs Seanus dc V Academie dcs Sciences, Vol. 163, Xo. 14, pp. 338-340. 

 Paris, October 2, 191 6. 



A series of experiments were carried out with cow pox vaccines in or- 

 der to determine the length of time, if any, which must elapse between 

 inoculation and immunisation. A very pure vaccine was injected into 

 the veins or arteries of rabbits, and immunity was tested by local reac- 

 tions. The results show that the time required for immunisation varies 

 inversely with the amount of vaccine injected, so that though it may not 

 be possible to suppress completely the latent or incubation period, it is 

 easy to modify its duration. Individual differeiices in the subjects are 

 far less important than the amount of vaccine used. Other investiga- 

 tors (BousQUET, Husson, Heim and Gregory) who have not taken into 

 account either the activity of their vaccine, or the size of their doses have 

 obtained very contradictory results with regard to the period of incuba- 

 tion, and the above experiments offer a satisfactory explanation of the 

 discrepancies recorded. 



1 161 - The Royal Institute for Agricultural Experiments Tripoli. — mangano g., in 



Ministero delle Colonie, Ufficio Economico, Bollettino di Informazioni, Year V, Nos. i, 



2 and 3, pp. 7-122. Rome, January, February' and March igi6. 

 One of the first duties of the Agricultural Department (" Ufficio 

 Agrario ") of Tripoli has been to found an experimental station for the 

 improvement of existing agricultural practice in the colony and to extend 

 the area of cultivated land. The station was established in the autumn 

 of 1914 at Sidi el Mesri, on the outskirts of the city of Tripoli, where build- 



EXPERIMENTAL 



AND 



ANALYTICAL 



WORK 



([) .Sse Din;lcr's polylech. Journal (1868) 188, 197; Zeifschrift fiiy annlytischc Chemie (1914) 

 53. 561 (Ed). 



