MICRO-ORGANISMS AS EXCITING AGENTS OF DISEASE. 93 



tagium and of the diseased body, or whether it is the important 

 active constituent. Much has already been gained by these 

 views which, though they may only represent a transitional 

 period in our knowledge, will prove a lasting gain. In place 

 of the unintelligible view that the diseased body, or the 

 disease itself, forms the contagious material, we have the 

 opinion that the formation of the contagium is a reproductive 

 process, and that the disease is the result of the reproduction 

 of this extraneous being in the organism and at its expense. 

 From this point of view we must interpret the symptoms of 

 the miasmatic contagious diseases. 



" While we must hold that the cause of the miasmatic con- 

 tagious diseases is a material endowed with independent life, 

 which can reproduce itself after the manner of animals and 

 plants, can increase by assimilation of organic materials, and, 

 growing parasitically on the infected body, can give rise to 

 the symptoms of the special disease, yet the question arises 

 of what the as yet unseen body of this parasite is composed, 

 the result of whose life is so evident and so devastating. It 

 is one of the laws of human phantasy that we must ascribe to 

 the contagium, as soon as we reckon it to be something living, 

 one of the forms which the known organic world presents to 

 our senses; hence in the earlier childish times of research 

 one thought of insects, and when the microscopic animals 

 were discovered, the infusoria could, with still better grounds, 

 be accused of being contagium and miasma. At the present 

 time, since the conclusions that have been arrived at with 

 regard to the fungus of muscardine and similar diseases, it 

 seems more likely that the contagium belongs to the vegetable 

 world, because the extensive distribution, the rapid multipli- 

 cation, and the tenacity of life of the lower microscopical 

 vegetable beings, as well as the mode of their action on the 

 bodies which they have selected as the seat of their vegetation, 

 present in fact the most remarkable analogies with the infec- 

 tive material of the miasmatic contagious diseases. Muscar- 

 dine also arises in stagnant marshes, apparently independently, 

 as if it were due to miasma ; under the influence of heat and 

 drought it becomes epidemic and contagious. Towards the 

 cessation of the epidemic its contagiousness diminishes, and 

 ultimately becomes lost. Currents of air carry the contagium 

 over long distances, so that the disease appears again in 

 another place, under the aspect of a miasmatic affection. The 

 contagium is an aeriform, and at the same time a fixed, body 

 It retains its power for years in a dry state. An imponderable 

 and incommensurable quantity of it is sufficient to set up the 

 disease, and even to produce devastating epidemics." 



