128 McAlpine, The Romance of Plant Paihology. \^'%^'^^' 



are much annoyed by such appearances. The trouble is some- 

 times attributed to the red dye used in branding bags ; but a 

 miller naively remarked to me that this could not be the cause, 

 as red spots appear in flour from mills where the bags are branded 

 blue. It is now known to be due to a microbe called Bacillus 

 prodigiosiis, the specific name being given on account of the 

 minute size of the organism. The cell contents form a blood-red 

 colouring matter, which is insoluble in water but soluble in 

 alcohol, and it resembles certain aniline dyes in many of its 

 reactions. This microbe is always present in the atmosphere, 

 and, since it may arise in the course of a single night as blood-red 

 slimy drops on stale bread, boiled potatoes, &c., this has given 

 rise to the stories of " bleeding bread," " bloody sweat," " blood 

 rain," &c. 



Dr. Bull, in his lecture on " The World without Microbes," 

 has given a very vivid picture of the work done by these tiny 

 organisms, and the possible failure of our food suppl}^ in their 

 absence. He classified them as the " criminal microbes," pro- 

 ducing disease and death, and the " artisan microbes," working 

 ceaselessl}' and rendering possible the existence of plants and 

 animals ; but he omitted to mention the miracle-working 

 microbe, as this one has produced the " bleeding Host " — the 

 consecrated l)read of the Eucharist. 



Professor Trouessart, in his work m the International Scien- 

 tific Series, entitled " Microbes, Ferments, and Moulds," refers 

 to it as follows : — " Many phenomena which have struck the 

 imagination of ignorant and credulous people are merely due 

 to the presence of these coloured microbes. In 1819, a peasant 

 of Liguara, near Padua, was terrified by the sight of blood- 

 stains scattered over some polenta which had been made and 

 shut up in a cupboard on the previous evening. Next day 

 similar patches appeared on the bread, meat, and other articles 

 of food in the same cupboard. It was naturally regarded as 

 a miracle and warning from heaven, until the case had been 

 sul)mitted to a Paduan nativalist. who easily ascertained the 

 ])ri'scnce of a microscopic plant, which Elurnbeig likewise found 

 at Berlin under analogous circumstances, and which he named 

 M())ias prodigiosa . ' ' 



With reference to j^olenta, it may be mentioned, in passing, 

 tiiat it is attracting a good deal of attention at the present time 

 as the probable cause of the disease pellagra. This disease is 

 a very serious one, and occurs chiefly in Italy, as well as numerous 

 other countries, and it has hitherto been attributed to eating 

 damaged maize, which is so largel}^ consumed as " polenta," the 

 porridge of Italy. There is a Pellagra Investigation Committee 

 formed in London, and the field commission at jiresent in Ital\- 

 consider that a parasite is the cause. 



