1198 Journal of Applied Microscopy 



incubator of which the atmosphere was saturated with moisture. Thus drying 

 of the gelatin was prevented and a sufficient amount of oxygen was provided. 

 Experiments showed that the results obtained from these conditions warranted 

 the trouble necessary to provide them. The atmosphere of the incubator may 

 be easily kept nearly saturated by shallow pans of water placed beneath the 

 shelves, and ventilation of the dishes may be accomplished in a number of ways. 

 I have recently had made a very convenient form of ventilated dish, which is 

 shown in the accompanying diagram. The cover is supported about 'J mm. 

 above the lower plate by means of three projections of glass, which are merely 



^£ 



•y 



indentations in the cover, obtained by heating the edge and pressing in the 

 softened glass with a sharp point. The sides of the cover are made deeper 

 than in the Petri dish by an amount about equal to that which the cover is 

 raised above the dish. With the cover thus elevated there is abundant op- 

 portunity for a free circulation of air, as indicated by the arrows. Ordinary 

 Petri dishes may be thus ventilated, but unless the work is done by a skilled 

 glass-blower the breakage is liable to be great. Furthermore, the cover of the 

 ordinary Petri dish is too shallow. 



If the ventilated dish is desirable for the cultivation of aerobic bacteria, it is 

 even more necessary for the cultivation of anaerobic forms. When these ventilated 

 dishes are placed in a jar, like the Novy jar, for example, the air in them may 

 be easily replaced with hydrogen, while with the ordinary Petri dishes this is 

 sometimes a difficult matter. George C. Whipple. 



Mt. Prospect Laboratory, Brooklyn, N. Y. 



As a result of the investigations on malaria carried on in Italy by Professors 

 Celli and Grassi, the Italian government will soon consider the appropriation of 

 a sum of money to continue the work already begun. Employers of labor in 

 malarial districts will be compelled to provide the proper precautions against 

 infection, and also supply medical aid to laborers who contract the disease, at the 

 same time providing a fixed amount for the support of their families when the 

 employer fails to comply with the requirements of the bill. 



