1923] Proceedings of the Academy of Science 15 



nated by Quercus Caieshaei (Turkey Oak) and Aristida stricta. 

 Both of these together with a number of other plants show striking 

 adaptations to this unusual habitat. 



The above two habitats and their respective communities are found 

 in the coastal plain and are sufficiently distinctive to give them a 

 place among the major plant associations of the state of North 

 Carolina. 



A New Vacuum Gage. Marston Lovell Hamlin, 



A vacuum gage is described, the basic principle of which is the 

 same as that of the McLeod and Gross gages, but in which the com- 

 pression of the residual air in the gage to a definite volume is brought 

 about without the use of a mercury leveling bulb or plunger. The 

 gage is rotated about a fixed axis and the small amount of mercury 

 in the gage is thereby poured down a tube, trapping a definite volume 

 of air. The inclination of the gage is adjusted so that the head of 

 mercury on the imprisoned air is sufficient to compress it to a prede- 

 termined volume, and the pressure corresponding to that inclination 

 is read off on a segment of a circle graduated to read directly in milli- 

 meters of mercury. 



The gage may be constructed with two or more working ranges, as 

 for example. Range 1, 0.1-15.0 mm ; Range 2, 0.01-1.500 mm, etc. 



Recent Improvements in Amoeha Culture Methods. Lloyd M, 

 Bertholf. 



The author, after pointing out the non-dependibility of the methods 

 of culturing amoebae ordinarily employed, gives a method worked out 

 by J. G. Edwards at Hopkins and somewhat modified by his own ex- 

 periment. A hay infusion is made of timothy hay and spring water ; 

 this is allowed to stand until it clears; it is then inoculated with 

 Amoeha proteus; and in a few weeks the amoebae appear abundantly, 

 feeding on the flagellate protozoon Chilomonas. The author gives a 

 few hints as to how to mix the infusion and how to keep it going for 

 several months, and by transferring occasionally, for years. A dis- 

 cussion is given of the reasons why the timothy hay cultures produce 

 such good results in rearing amoebae. 



