ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 377 



Stained, whereas those containing B. coli were clouded and decolorised in 

 the case of copper sulphate, and stained green by the prussiate of potash. 



Modification of Fermi's Method for the Examination of Proteolytic 

 Enzymes.*— S. L. Schouten adds water saturated with thymol to 7'5 

 p.c. of gelatin, and as much powdered cinnabar as will make the fluid 

 deep red ; by stirring well the cinnabar is prevented from settling, and 

 the mixture is then poured through a long-necked filter into test tubes, 

 about 5 c.cm. into each ; these are then placed in a water-bath at 40° C, 

 and then held for 10 seconds under a cold water tap, the gelatin being 

 thereby thickened but not solidified ; when the tubes are stood vertically 

 there will be a thin elhptical layer of gelatin attached to the wall of the 

 tube ; when thoroughly cooled the fluid to be examined is introduced 

 into the tubes, with an addition of a piece of thymol. The object of the 

 method is that the enzyme comes into contact with a large surface of 

 gelatin, which being in only a very thin layer can be quickly liquefied. 

 All the tubes must be heated to the same temperature, and cooled for 

 the same length of time. The author claims that by this method it is 

 possible to determine after 12 hours whether an enzyme is present, and 

 to estimate how quickly it acts. 



Cultivating a Micro-organism found in the Blood in cases of 

 General Paralysis.! — N. Sokalsky obtained blood from three cases of 

 general paralysis, and inoculated tubes of agar, gelatin, potato and broth. 

 Cover-slip preparations made after 24 hours in a thermostat and stained 

 by Bocardi's method and with 1 p.c. alcoholic eosin, showed many round, 

 highly refractile bodies inclosed in the red corpuscles, as many as 20 

 being contained in one cell ; these bodies were larger than micrococci, 

 stained badly with anilin dyes, but well with concentrated fuchsin, and 

 by 1 p.c. alcoholic eosin ; not staining by Gram's method. 



Broth cultures remained clear with a slight deposit which is composed 

 of the same round bodies arranged in pairs or in bundles like sarcin*. 

 Guinea-pigs inoculated subcutaneously with the broth culture developed 

 paralytic symptoms, and the organism was re-obtained from the heart- 

 blood after death. 



Automatic Aerating Device for Aquaria. J — L. Murbach obtained 

 very gratifying results from the apparatus for aerating aquaria which he 

 invented, and thus describes : 



The things needed are a glass filter pump, two wide-mouthed bottles 

 about 8 by 15 cm. and 6 by 12 cm., a cork stopper to fit the larger 

 bottle, a stand with balance beam, glass and rubber tubing. The stopper 

 is bored with three holes, 5 mm., 8 mm., and 11 mm. in diameter. 

 Into the smaller holes are fitted a 24 cm. long tube for the air outflow, 

 and a 15 cm. long tube for carrying the water from the filter pump. 

 The 11 mm. hole is for a wooden rod 15 mm. in diameter and about 

 15 cm. long ; this is cut down, tapering abruptly from 15 mm. to 8 mm. 

 the rest of its length. The larger end of this rod serves as a valve in 

 the 11 mm. hole in the stopper, being placed vertically so that the 



* Centralbl. Bakt., 2te Abt., xviii. (1907) p. 94. 

 t Op. cit., Ite Abt. Orig., xliii. (1907) p. 213. 

 X Amer. Naturalist, xli. (1907) pp. 61-4 (1 (fig.). 



June 19th, 1907 2 c 



