The Microscope. 331 



ulai* manner in question. Nothing has been noticed as to the dif- 

 ference, if any, in the different varieties in regard to the liability of 

 infection. Yery probably there is some variation in this respect. 



According to the tenth census of the United States, there were 

 produced in 1879, 12,7U2 lbs. of sugar and 28,444,207 gallons 

 of molasses from sorghum, and 29,480,100 lbs. of broom-corn. 

 Counting the sugar at live cents per lb., the molasses at thirty-live 

 cents per gallon, and the broom- corn at one hundred dollars per ton, 

 and estimating the loss from this disease as five per cent, of the 

 entire sum, which is certainly far within the actual amount, we have 

 $571,506.00 as an annual tribute laid upon these comparatively unim- 

 portant crops in our country by the microscopic invaders, belonging 

 to a single company of the mighty host which we are just beginning 

 to recognize as warriors and enemies. Is it not time that we were 

 opening our eyes and bestirring ourselves for a determined engage- 

 ment ? Victory ought to be, and may be, ours. 



Having now presented the chief results of these investigations, 

 permit me to recall attention to the fact that this plant disease is started 

 by simply placing the living microbes on the healthy leaves. There 

 is no wound of any kind as a prerequisite. There is no preliminary 

 letting down of constitution vigor. The action of the bacteria is 

 direct and indisputable. They, and they alone, must be considered 

 the agents of the injury. It is by no means asserted that this is the 

 first time such proofs have been offered, or that the work in this case 

 has been exceptionally well done from the standpoint of general 

 bacteriology; but, upon the principle of line upon line, the results 

 must help to strengthen testimony already strong. 



It only remains to introduce the new member of the family of 

 known microbes as Bacillus sorghi, n. sp. 



Champaign, III. 



COLLECTING AND CLEANING DIATOMS. 



K. M. CUNNINGHAM. 



MY apology to the I'eaders of The Microscope for adding 

 another article to the many that have preceded, in relation 

 to the subject title at the head of this, may be found in the receipt 

 of a flattering invitation, coming from the managing editor, to contrib- 

 ute an article of this nature. During the past six months I have given 

 very close attention to the subjects of collecting and cleaning, or pre- 

 paring, the diatomacete. So much so that I enter, without hesitancy. 



