548 SUMMARY OF CURRENT RESEARCHES RELATING TO 



fixation reaction in determining the presence of typhoid bacilli in water. 

 The water is filtered through a Chamberland filter: the deposit is 

 scraped off ami mixed with normal .saline. To a measured quantity of 

 this are added 2 drops of a strong anti-typhoid serum, 1 drop of comple- 

 ment, and 1 c.cm. of sensitized Hood-corpuscles. The absence of 

 hemolysis indicates the presence of typhoid bacilli. By actual trial the 

 authors have determined that the method is much more delicate and 

 reliable than the culture methods at present in use, and it is just as easy 

 of application. 



Collodion Filters.*— J. Duclanx and A. Hamelin make some obser- 

 vations on the use of collodion filters, based on an experience of several 

 years. The usual difficulty in their use is that they cannot be dried 

 or sterilized by heat. The authors have succeeded in preparing cellu- 

 lose filters which obviate these difficulties, but the results are not 

 constant enough to be satisfactory. These were prepared by mixing a 

 solution of cellulose with Schweitzer's fluid, but much better results 

 have been obtained by denitrifying nitrocellulose, the best agent for 

 the purpose being ammonium sulphohydrate. These filters can be dried 

 any number of times, or placed in boiling water without being affected. 

 They also resist the action of alcohol, ether, and acetone. In filtering 

 liquids containing very fine particles the process is very slow. It is im- 

 possible to use air-pressure lest the filter be ruptured, and the device is 

 recommended of using osmotic pressure as an accelerating agent. To 

 this end the authors employ a solution of Congo red, which does not 

 penetrate the cellulose filter, but exerts a considerable osmotic pressure 

 upon it. By this means they were able to increase the rapidity of filtra- 

 tion by as much as seven times without endangering the filter. 



Resistance to Passage of Microbes through Collodion Filters.f 

 Grenet and Salimbeni have succeeded in preparing a collodion filter for 

 general use. Their method is to dip an ordinary Chamberland candle 

 into a solution of collodion containing 10 p.c. of glycerin. The glycerin 

 prevents the filter drying and so becoming useless. Before doing so it 

 is necessary to remove all the air from the candle by plunging it in water, 

 or, better, in alcohol. Such a filter prevents the passage of ultramicro- 

 scopic organisms, and it retains its efficiency for at least a year. It does 

 not become clogged like an ordinary Chamberland. To prevent the 

 growth of moulds upon it, it is advisable to add a trace of formalin to the 

 collodion solution. 



Rapid Method for Isolating Oospora lingualis.J — F. Gueguen 

 states that carrot is the least unfavourable medium for isolating Oospora 

 lingualis, a parasite found in cases of black tongue. The carrot is inocu- 

 lated by stroking the surface with an affected papilla. In about five 

 days the growth will be evident above the general surface. A trace of 

 the growth is removed and sown in liquefied gelatin ; a second tube is 

 inoculated with a drop of the first, and from the second a third tube is 

 similarly inoculated. Sometimes it is necessary to make a fourth and 



* Ann. Inst. Pasteur, xxv. (1911) pp. 1-15-9. 

 t Comptes Rendus, clii. (1911) pp. 916-19. 

 % C.R. Soc. Biol. Paris, lxx. (1911) pp. 752-3. 



