THE OEIGIN AND PROPAGATION OF DISEASE. 231 



Microsporo7i, by Kobner,* in 1864. The fungus-spores, transplanted upon 

 the skin of other individuals, or upon other parts of the skin of the 

 patient, after a certain interval germinate and multiply, and so create a 

 secondary focus of the disease. The contagious character of the malady 

 is thus seen to depend, not upon a virus, in the old sense of the word, 

 but upon the actual communication of reproductive germs, which give 

 origin in their new location to a vegetative growth similar to the old. 

 The vegetable growth, therefore, precedes the disease, and must be 

 regarded as its cause rather than its consequence. 



The actual transportation of these germs through the air is also a 

 matter of demonstration. Lemairef placed glass jars filled with ice in a 

 shallow basin, so that the condensed moisture of the atmosphere, depos- 

 ited upon the cold sides of the glass, might trickle down and collect in 

 the basin below. He then applied friction to the head of a boy with 

 favtis, near by, and found that the spores of achorion were floated by 

 the air-currents for a distance of twenty inches into contact with the 

 jars; and then, being entangled by the condensed moisture, were carried 

 down into the basin. He sometimes found as many as thirty spores in 

 a single drop of condensed moisture. 



The second part of the test is equally well established. I presume 

 that dermatologists are now fully agreed that, for all cutaneous affections 

 known to be characterized by the presence of a microscopic fungus, the 

 one essential element of cure is the application of some parasiticide which 

 shall destroy the vitality of the fungus. Iodine, sulphurous acid, or mer- 

 curial bichloride, by killing the vegetable, as sulphur-ointment kills the 

 animal parasite of scabies, in simpler cases absolutely puts an end to the 

 disorder, and in the more comx^licated ones leaves behind only secondary 

 symptoms, which have no longer any specific or contagious character. 

 Of course there are various points relating to these affections which are 

 still more or less in doubt. Some microscopic cutaneous fungi have been 

 described as distinct species, which have not received general recogni- 

 tion, and some observers are disposed to question whether the three 

 principal ones may not all be simple varieties or forms of development 

 of the same plant. 



But there are similar j)oints of difference still existing among scientific 

 botanists with regard to microscopic fungi in general 5 and I believe that 

 the three principal facts of (1) specific parasitic vegetation as a cause of 

 cutaneous disease; (2) its propagation by the transport and germination 

 of spores; and (3) its treatment and cure by parasiticide applications, 

 may now be regarded as wholly beyond a reasonable doubt. 



I have alreadj^ alluded to the remarkable activity of botanical research 

 of late years in the department of cryptogamic vegetation. The most 

 strikmg results have been attained by these investigations, in increased 

 knowledge of the modes of development and reproduction of these organ- 



* Cited in Neumann's "Handbook of Skin-Diseases," translated byDr. L. D. Bulkley, 

 New York, 1872, p. 434. 



t '•'Coniptes Eeudus de l'Acad6mie des Sciences," 1864, tome lix, p. 127. 



