SCIENCE. 



207 



glands — and the rods occurred in greatest numbers in 

 such morbidly changed parts and morbid products — for 

 instance, in the ulcerous tumors of the intestines — as are 

 accessible to atmospheric air and other external influences. 



The constant occurrence of these Schizophytes soon made 

 it appear probable that their presence is not merely acciden- 

 tal, but that the same, very likely, are connected with, and 

 characteristic of, the morbid process of the disease. To 

 get at the facts was one of my principal endeavors. How 

 far I have succeeded I leave to others to judge. 



Careful and repeated macroscopic and microscopic ex- 

 aminations of the tissues, but especially of the lungs, 

 which, by the way, are always more or less affected by 

 the morbid process of Swine-plague, soon revealed the 

 fact that the principal morbid changes are brought 

 about in the following way : The finer capillary blood ves- 

 sels become obstructed or plugged, the more fluid por- 

 tions of the blood exude into the tissues — in the lungs 

 principally and at first into the lobules, and then into the 

 interlobular connective tissue — some, and particularly in 

 young animals not seldom but a great many, of the finest 

 capillaries rupture, and innumerable small extravasations 

 of blood, visible to the naked eye as tiny red spots, are 

 deposited into the tissue. In the skin, subcutaneous tis- 

 sue, and intestinal membranes the process is essentially 

 the same, but to folldw it further would lead too far for 

 the present. Let me, therefore, mention another fact. 

 While the blood taken from a vein of a diseased or dead 

 pig invariably contains a large number of spherical bac- 

 teria or Micrococci, and very few, and usually small Zob- 

 glcea-masses, the diseased parts of the lungs, and especi- 

 ally the stagnant blood, which oozes out of the 

 capillaries, if the diseased parts of the lungs are cut into 

 small pieces, invariably contains, besides Micrococci, 

 numerous and large Zooglcea-masses, which are, most of 

 them, much larger than the blood corpuscles, and abund- 

 antly large enough to clog the finer capillaries. All this, of 

 course, does not.-prove that the Schizophytes constitute 

 the cause of the morbid process. I therefore resorted to 

 experiments. Having found that any inoculation of a 

 healthy pig with the fresh pulmonary exudations of a 

 diseased or dead animal invariably produces the disease 

 in three to fifteen days, or on an average in six 

 days, I concluded it might be ascertained in two 

 different ways — in a negative and in a positive 

 way — whether or not the Schizophytes constitute the 

 cause of the morbid process. If it were possible to 

 free the Schizophytes from everything, and to transfer 

 the same v ithout any vehicle whatever from one animal 

 to another, for instance, like a louse or an itch-mite, the 

 question would be very soon answered. But as that 

 cannot be done, I had to get at the facts in a more indi- 

 rect way. I repeatedly charged two ounces of an innocent 

 fluid, at first pure and fresh milk, then boiled milk, mut- 

 ton broth, afterwards water, and finally albumen, with one 

 drop of the infectious pulmonary exudation, containing 

 an abundance of Schizophytes. In about three days 

 the fluids thus charged, which, by the way, were kept at 

 a suitable temperature, were found to be swarming with 

 Schizophytes, identical in appearance to those found in 

 the pulmonary exudation ; and every inoculation made 

 with these fluids proved to be effective, but in most cases 

 the attack produced was of a comparatively mild type. 

 To go further into particulars would take too much time; 

 I therefore have to refer for particulars to my reports to 

 the Commissioners of Agriculture. One thing, however, 

 I must state. The fluid transferred by each inoculation 

 was less than half a drop, but this half drop contained 

 innumerable Schizophytes, while as far as could be ascer- 

 tained by careful microscopic examinations, nothing else 

 contained in the original exudation had multiplied. Con- 

 sequently, nobody, unless he believes in the power of 

 Hahnemannian dilutions, will contradict, and say, the 

 effect of the inoculations is brought about, not by the 

 Schizophytes, but by an unseen and unknown virus, or 



chemical something, the existence of which cannot be 

 proved. I was, however, not satisfied with these positive 

 results, and concluded to try also the negative way. 

 Knowing that it is impossible to separate the Schizophytes 

 from their vehicle, I tried to free the latter from the Schiz- 

 ophytes, and resorted to filtration. I filtrated the pul- 

 monary exudations through half a dozen of the finest 

 filtering papers obtainable, but found my effort to be in 

 vain, for the filtrate, although freed from the Zooglcea- 

 masses and rod-shaped bacteria, yet contained numerous 

 Micrococcus-forms. The filtrate was put in a vial with a 

 tight fitting glass-stopper, and when examined three clays 

 later, it contained a great many rod-shaped bacteria, and 

 comparatively few Micrococci. I therefore filtered it again 

 with the same result, except that the Micrococcus-forms 

 were not as numerous after the second filtration as after the 

 first. So I filtered the exudation three or four times, 

 each time through four to six filtering papers, and at in- 

 tervals of about three days till I was finally not able to 

 detect any Micrococci in the now limpid filtrate. Inocula- 

 tions with this filtrate proved to be ineffective. At 

 another time — in the following winter. — I tried again to 

 free pulmonary exudation from the Schizophytes by 

 means of filtration, but did not succeed. The filtrate 

 always — after each- filtration — contained numerous 

 Micrococci. Whether, in this second attempt, I did not 

 hit the right time for my second and third nitrations, 

 that is, a time at which most or all of the micrococci had 

 developed to rod-shaped Schizophytes or filaments; 

 whether the temperature was too low — the first, success- 

 ful attempt was made in the summer — and therefore the 

 development of the Schizophytes was irregular or retarded ; 

 whether my filtering papers were not fine enough ; or 

 whether all these circumstances combined made the fil- 

 tration a failure, I do not know. An inoculation made 

 with this filtrate proved to be effective, but the disease pro- 

 duced was of a very mild character ; at any rate, the ani- 

 mal recovered. 



If more proof is yet required that the Swine-plague- 

 Schizophytes and nothing else constitute the infectious 

 principle of that disease, and it seems that the above 

 facts which have been published more fully in my reports 

 to the Commissioner of Agriculture, are not deemed 

 sufficient, the following facts, if not making it absolutely 

 certain, will at any rate, especially if considered in toto, 

 to a great extent, corroborate the assertion that the Schizo- 

 phytes have, and must have, a causal connection with 

 the morbid process. 



1. It has been, and can be, everywhere observed, 

 where Swine-plague is prevailing, that the infectious 

 principle floating in the air, is attracted and taken up by 

 sores, wounds and even scratches, but does not enter the 

 animal organism through the whole skin and through 

 perfectly healthy respiratory mucous membranes. 



2. Antiseptics, or medicines, which are either directly 

 poisonous to the lower forms of organic life, or destruc- 

 tive to those conditions, under which low forms of or- 

 ganic life thrive and develop, and among those antisep- 

 tics, especially carbolic acid, iodine, hyposulphite of soda, 

 benzoate of soda, thymol, etc., have proved to constitute 

 almost sure prophylactics. As one of the conditions 

 necessary to the development of Swine-plague bacteria, 

 it seems, has to be considered a certain degree of animal 

 heat. At any rate, after, and while the animal heat of a 

 pig is reduced by a continued treatment with carbolic 

 acid, from the normal (102 to 104 F) to an abnormally 

 low temperature (say 96 to 97 F), every innoculation 

 with fresh infectious material has so far proved to remain 

 ineffective. Further, the various antiseptics, which have 

 proved to be good prophylactics, are very dissimilar in 

 their chemical affinities and actions, and their prophy- 

 lactic effect cannot very well be explained, if the infec- 

 tious principle were a chemical agency, a virus, or a poi- 

 son, but is explained, if the same consist in something 

 endowed with life and power of propagation. 



