774 SUMMARY OF CURRENT RESEARCHES RELATING TO 



suspended in the cold, can alter the germs and hinder the development 

 at ordinary temperatures. In the ice chamber the blood remains 

 virulent for a less time in an open tube than in a closed one; but 

 though the virus maintained its strength for at least three months in a 

 sealed capsule, it became inactive after three days in a vacuum. In 

 colloidin capsules placed in the peritoneum of a rabbit, the virus 

 perished within four days. The addition of glucose and pepton in 

 varying proportions enables the virulence to be retained for a longer 

 period. For purposes of culture, therefore, the author limits the 

 quantity of blood, and uses glucose-pepton-agar as a medium. 



Detection of Indol in Microbial Cultures.* — G. Buard has adopted 

 the following method for the detection of indol : 10 c.cm. of culture 

 are mixed in pepton water, and after 15 to 20 hours' incubation, 

 o-6 c.cm. of absolute alcohol are added, and after mixing there is 

 added 1 c.cm. of alcoholic solution of vanilin and 3 c.cm. of pure 

 hydrochloric acid. If indol is present it develops a pink coloration 

 which becomes more intense, deepening to a red-magenta or violet-red, 

 especially on the application of slight heat. The author experimented 

 with several varieties of pepton. With the pepton of Defresne the 

 pink colour changes to saffron. The author claims for this method 

 great certainty of results and much saving of time. 



Method of Fixing the Eggs of Ascaris megalocephala.f— C. Artom 

 leaves uteri in salt solution until most of the eggs reach the desired 

 stage of development. Little heaps about " 5 cm. high are placed on 

 a carbonic acid freezing-microtome, and when frozen the mass is 

 sectioned. Though many eggs are of course irretrievably damaged by 

 this procedure, yet a good few will be found with only a thin slice re- 

 moved from the shell. The sections, which should be about 30 /i 

 thick, are transferred while still frozen from the knife to the fixative, 

 such as Flemming's strong solution, sublimate-acetic acid, formol- 

 alcohol, picro-acetic acid. The blackening from osmic acid must be re- 

 moved by immersion for several days in turpentine oil. Borax-carmin 

 and dilute Delafield's hasmatoxylin give good results for preparations 

 fixed in Flemming's solution. The fixed eggs were examined m toto or 

 imbedded in paraffin and sections made. 



Celloidin Decalcification and Desilication.J — C. F. Bodecker gives 

 the procedure for removing lime and silica from organic material in 

 minute detail. § After fixation the material is passed through the fol- 

 lowing fluids : alcohol 40 p.c. (1 hr.) ; alcohol 70 p.c. (^ hr.) ; alcohol 

 96 p.c. (|hr.); absolute alcohol (12 hr.) ; ether and absolute alcohol 

 (1 hr.) ; thin celloidin (12 hr.) ; acidulated celloidin (1 week to 2 months). 

 (This mixture consists of celloidin solution, to which 10 p.c. nitric acid is 

 added. The acid is mixed with ether and alcohol and gradually added to 

 a celloidin solution, stirring the while.) 



During decalcification it is necessary that evaporation should be 



* C.R. Soc. Biol. Paris, lxv. (1908) p. 158. 



t Zeitschr. wiss. Mikrosk., xxv. (1908) pp. 3-7. J Tom. cit.,pp. 21-9 (1 pi.). 



§ See this Journal, 1905, p. 764. 



