1897 | CURRENT LITERATURE 447 
of the chromogenic bacteria have the power of evolving oxygen. This is 
demonstrated in the following manner: A small quantity of the chromo- 
gene to be tested is placed on a cover glass, and to this is added a drop of 
fluid but cool gelatin. When solidified a drop of water containing actively 
motile aerobic organisms is also added, and the whole at once covered. If 
certain chromogenic bacteria are used, the motile forms in close proximity to 
the gelatin will continue to move for hours, whereas such movement is sus- 
pen in a few minutes if no chromogenic culture is added. Further proof 
that the evolved gas is oxygen is shown by the ability of the gas to reoxidize 
reduced indigo carmine. The addition of HgCl, stops the evolution, and as 
it occurs in darkness, it cannot be regarded as a photosyntactic product. 
Ewart arrives at the conclusion that the evolution is a purely physical proc- 
ess, the bacterial pigment having the power of absorbing oxygen, then 
gradually evolving it again. The oxygen is held in much the same way as 
it is in oxyhaemoglobin. The biological significance of this process is a 
question asked but unanswered. 
The chlorophyllose and purple bacteria are also considered in relation to 
their oxygen evolving properties. Engelmann’s proof for the evolution of 
oxygen from these green bacteria was by exposing them to cultures of some 
spirillum, but Ewart claims to nes te able 8 ane papers deat from a 
turesof these forms. He also 
tosyntactic powers, although this property is nes marked. The akcbiicn§ is 
that the evolved oxygen in these cases is the result of photosyntactic activ- 
ity.—H. L. RussELL. 
THREE STATION bulletins of recent date having botanical interest are 
the following; J. C. Whitten (Mo. no. 38, pp. 140-164) shows with excellent 
data that the winter killing of the flower buds of peach may be greatly les- 
ys 
other reflects them. The former is especially effective, while the latter saved 
_ 80 per cent. of the buds when only 20 per cent. survived unprotected. J. F. 
Duggar (Ala. no. 87, pp. 459-488) Les the result of inoculating the soil for 
-vetch, peas, clover, lupine, and other leguminous plants, with soil in which 
_ such plants had previously grown and with the imported commercial article, 
known as nitragin, in both pot and field culture. Results largely favored the 
inoculated plants. P.H. Rolfs (Fla. no. 41, pp. 517-543) announces the 
occurrence in Florida,and possibly in California, of an important fungous 
parasite of the very destructive San Jose scale insect. It is Sphaerostilbe 
coccophila Tul., native of warm countries, United States and elsewhere. It 
_ clears the tree of insects more thoroughly than any artificial means so far 
: devised. The infection is easily disseminated from both natural and labora- 
ach grown material ate C. x. 
