Zymotic and Germ Diseases. 207 



In many cases the virility of the race of disease-producing cells seems to reach a cul- 

 mination and then decline, becoming' less and less vigorous, the epidemic declining liotli 

 in the number of people affected and in the violence of the disease, till it finally dies 

 out as if of old age. And that, I take it, is precisely the case. Otherwise, why should it 

 ever stop? It must be that the repeated modifications of the disease cells brought about 

 by the constant or repeated reactions against them of the united cell organization of the 

 body , finally alters them into a condition in which they can be either assimilated or 

 ejected, or in which they are at any rate harmless. 



The investigators who have given the subject of fermentation the most put lent atten- 

 tion, and who ought to know, regard the soluble ferments as inorganic, that is, while 

 they are products of organisms, they are only manufactured articles, which by virtue of 

 their composition and make up, produce certain effects upon infusions and animal fluids, 

 but which do not reproduce their kind by a gemmation or fission. If the theory in dis- 

 eases, of fermentation, or of "germs," "bacilli," "vibrios," "microbes," or anything of 

 the sort, or all of them is to be adopted, it seems consistent to include an insoluble zymase 

 as the product and companion of the self-reproductive organism, as it is of thesaccha- 

 romyces, &c. Where the two go together, it is easy to see their possible competence to 

 achieve the mischiefs of contagion, &c. But there is also this probability; that the 

 zymase may become separated from the organism which produces it, and carried through 

 the air to work alterations in such suitable fluids as it may meet .with. For example, 

 suppose the organic juices of a rich swamp to be the home of organisms, like the Torula 

 or other microscopic plants which give rise to their corresponding zymases. After awhile 

 the swamp dries up partly, and great numbers of the organisms become dessicated and 

 perhaps disintegrated. But the disintegration of an organized plant does not destroy its 

 zymase ; it only liberates it and allows it to be carried off by the air. I think many en- 

 demic zymotic diseases may be accounted for in this way. But if when the swamp dries 

 up, the organism itself is blown about, we get a regular germ disease. A disease arising: 

 from a zymase alone might be infectious because the zymase being a catalytic agent is 

 not supposed to lose much, at any rate not for a long time ; so after having " altered " the 

 blood of one victim it may be transferred to another in the dejecta and come to the 

 second attack with but slightly impaired powers. 



The circumstance that these diseases become reduced and finally die out, recall the 

 action of the soluble ferments. As shown elsewhere, if consecutive generations of these 

 ferment cells be cultivated in the same sort of a medium, after a time they become less 

 virile and active. In order to renew their vitality and activity it is necessary to trans- 

 plant them to another medium. The true theory of this phenomenon is without doubt 

 that the reaction of the medium in which the ferment cell is raised, modifies the cell it- 

 self and finally neutralizes its activity. 



The kind of cell, therefore, which lies at the basis of the malarial diseases, and some 

 others, is one which sets up an alteration in the blood or some other fluid. In consequence 

 of such alteration, the proper functions of such fluid are ill performed or not performed 

 at all. The different sorts of disease ferments, as they might be called, affect different 

 parts, as the secretions of the salivary glands in mumps, the secretions of the intestinal 

 glands in typhoid fever, the secretions of the pituitary or schneideriau membrane in in- 

 fluenza, the blood in several diseases causing fibrinous exudations in one part or another. 

 The elective quality on the part of these disease ferments is analogous to that ex- 

 hibited by vegetable and mineral poisons; thus "alcohol and opium exert their effects on 

 the brain, arsenic on the intestinal tract, strychnia on the spinal cord, mercury on the 

 mouth, phosphorus on the liver, aconite on the heart, &c.'' (Dr. Flint.) Different 

 lengths of time are required for the "incubation" of different sorts of these ferments, 

 some only a few hours, and some a number of days, or even weeks, just as different kinds 

 of yeast are a long or short time in leavening a batch of bread. But I suppose also some 

 of the tissue cells and fluids of the body are more easily disorganized than others, a fact 

 which may contribute to this difference. 



During the progress of an epidemic of a certain class, the fermenta- 

 tion is evidently communicated to deposits and collections of organic matter, such as 

 ponds of stagnant water, cess-pools, sewers, &c. Thus the sewers of Memphis had the 

 yellow fever during the two years in which that disease played such havoc with that 

 city. In the following season after they had taken measures to keep the miasm of the 

 sewers out of the houses, and had thoroughly cleaned and disinfected the sewers, al- 

 though the disease, was still prevalent along the Mississippi river, they escaped. From 

 this it would appeal- that the miasm of the disease pervading the air was deficient either 

 in the number of the disease cells or germs, or in their virility to produce an epidemic, 

 till these cells were reinforced by a fresh crop raised in the sewer,. 



