INDUSTRIAL PROGRESS DURING THE YEAR 1875. cxliii 



coal was pulverized and exposed to a white heat ; the de- 

 carbonized dust was treated with acid and chlorate of po- 

 tassa, washed clean with distilled water, and placed under 

 the microscope. Many diatoms, almost exclusively fresh- 

 water genera, and species now living, were found. A piece 

 of cannel-coal from Scotland and another from the St. Eti- 

 enne mines gave the same result. The experiment needs 

 repeating to prove that these organisms from the coal epoch 

 to the present time have undergone no perceptible modifica- 

 tion. 



In the Monthly Microscopical Journal for September, 1 875, 

 is an interesting paper by Worthington Gr. Smith on the 

 resting spores of the potato fungus, or the " new " potato 

 disease, as it has been called, and he shows that it is no 

 other than the old enemy in disguise, Peronospora infestans, 

 in an unusual and excited condition. The article is well il- 

 lustrated, and worthy the attention of microscopists interest- 

 ed in the study of these parasitic organisms. In the same 

 journal is the conclusion of Dr. Bastian's address on the 

 microscopic germ theory of disease, in which he insists that 

 the facts already known abundantly suffice to displace the 

 narrow and exclusive vital theory, and to re-establish a 

 broader physico-chemical theory of fermentation, and that 

 the original notion, borrowed from the vital theory of fer- 

 mentation, that all the organisms met with in a fermenting 

 mixture are strictly lineal descendants of those originally 

 introduced as ferments, must disappear with the vital theory 

 itself, and with it the old explanation of the mode of increase 

 of contagium within the body. 



A paper of some interest on the sphcerap hides in plants 

 appears in the Monthly Microscopical Journal for December, 

 1874. The author states that in Urtica dioica, U. ure?is, 

 and Parietaria diffusia the leaf blades are studded with 

 sphaBraphides about -^^ of an inch in diameter, composed 

 mainly of carbonate of lime ; smaller forms, with projecting 

 crystalline points, and composed of oxalate of lime, occur in 

 the fibro-vascular bundles of the leaf; the same two kinds 

 abound in the leaf and pith of Hamulus lupulus. 



Dr. Bastian delivered an address lately before the Patho- 

 logical Society of London, on the microscopic germ theory 

 of disease. The conclusion he has arrived at is opposed 



