December 21, 1888.] 



SCIENCE. 



311 



ries connected with Johns Hopkins University. These had Ijeen 

 recently built under the direction of professors familiar with the 

 best laboratories of Europe, and Dr. Hoagland could not have found 

 in Great Britain or on the continent any better models from which 

 to make his plans. We are indebted to him not only for the money 

 required to build and equip such a laboratory as this, but for his 

 constant personal supervision and attention to details, from the 

 first draughts of the plan until the moment of completion. I have 

 been consulted from time to time ; and the first visit to Baltimore 

 was followed by several others, in which Dr. Hoagland carefully 

 noted all of those minor details which go to make a laboratory com- 

 plete and comfortable. The result is, as you see, a building thor- 

 oughly suited to the purpose for which it was designed, and which 

 also, from an architectural point of view, is an ornament to the " City 

 of Churches." 



I have also been consulted with reference to apparatus ; and we 

 have here to-day, or on the way from Europe, every thing that oc- 

 curred to me as essential for the equipment of the laboratory. The 

 library has also been most generously provided for, and it is the in- 

 tention to have upon its shelves not only standard books of refer- 

 ence, but, so far as possible, complete files of the English, French, 

 and German periodicals relating to those branches of research to 

 which the laboratory is devoted. 



No one appreciates the advantages of such a laboratory as this 

 more than I do, and I would be happy if circumstances made it 

 possible for me to go into camp here during the balance of my work- 

 ing life. A pioneer in this country in the pursuit of bacteriological 

 studies, I have seen to open up before me a most inviting field of 

 research, presenting a multitude of important questions awaiting 

 solution by the experimental method, and I have learned by expe- 

 rience how little can be accomplished in the absence of suitable 

 laboratory facilities. 



I have felt from the first that this country ought to take some 

 part in the investigations relating to the etiology of infectious dis- 

 eases, which have resulted, within the brief period of twenty years, in 

 discoveries which will make this the most famous epoch in the his- 

 tory of scientific medicine. There can be no question that we have 

 plenty of men who have the necessary intelligence and zeal to make 

 them leaders in this or any other department of scientific investi- 

 gation, but we have sadly lacked just those facilities which are fur- 

 nished by this laboratory ; for intelligence and zeal caimot take the 

 place of training and a knowledge of the methods of research which 

 have been perfected by the patient labors of others. The young 

 man who starts out to make discoveries without such training is 

 like the old farmer, who, after churning for years with an old-fash- 

 ioned up-and-down, dash-churn suddenly conceives the idea that 

 a churn with a crank would be an improvement, and applies for a 

 patent, only to find that the same idea had occurred to thousands 

 before him, and that patents have been granted on crank-churns 

 of every conceivable form. 



Our library takes the place of the patent-examiner. And when 

 the trained investigator desires to follow any particular line of re- 

 search, his first step is to find out what others have done before him ; 

 his second, to consider whether known methods and instruments 

 will answer his purpose, and, if not, to devise and test such meth- 

 ods of research as occur to him. 



With this brief introduction, permit me to proceed with the spe- 

 cial subject upon which I am to address you. 



Leeuwenhoek, the father of microscopy, first discovered the mi- 

 nute organisms known as bacteria in putrid water and in tartar from 

 the teeth ; but it was not until the present century was well ad- 

 vanced that the true character of these micro-organisms, and the 

 important part which they play in the economy of nature, were 

 recognized. We know now, that although certain species are 

 pathogenic for man and the lower animals, and give rise to fatal 

 infectious maladies, the bacteria as a class are essential for the con- 

 tinued existence of the higher plants and animals upon the surface 

 of the globe and in the waters of the ocean. It is their function to 

 return to the earth and the air those elements and simple com- 

 pounds which go to make up the complex organic structures which 

 enter into the composition of the tissues of living plants and ani- 

 mals. So soon as the physiological processes upon which vitality 

 depends have ceased, either from external or internal causes inter- 



fering with the integrity of organs essential to life, these universa 

 destroyers commence their work, and those putrefactive changes 

 are inaugurated which result in the disintegration of animal and 

 vegetable tissues. It is evident, that, if no such disintegrating 

 agency existed, the surface of the earth and the waters of the ocean 

 would soon be encumberetl with dead plants and animals, and the 

 course of animate nature would be arrested, both by occupation of 

 available space and by exhaustion of nutritive material. 



These processes of decay, which in animal bodies exposed to the 

 air occur so promptly, under favorable conditions as to temperature 

 and moisture, are going on continuously in the upper layers of the 

 soil, where the roots of annual plants, and the organic material 

 turned under by the plough of the farmer, must be reconverted 

 into elementary substances which can be appropriated by growing 

 plants. In the ocean the same thing occurs, — the myriads of fish 

 and other living creatures which perish every day are quickly in- 

 vaded by these omnipresent micro-organisms, and undergo disinte- 

 gration. 



The question may be asked, ' What, then, becomes of these pu- 

 trefactive organisms, and what prevents them from taking full pos- 

 session of the waters of the deep ? ' Like other living organisms, 

 they have their life-cycle, and perish at the end of a given period, 

 and, like other living organisms, their multiplication is limited by 

 the amount of available material. Moreover, they serve as food for 

 a multitude of micro-organisms a little higher in the scale of exist- 

 ence, and especially for the Infusoria. 



Under this name — Infusoria — the older naturalists included all 

 of the minute unicellular organisms observed by them in putrefying 

 infusions. At present this name is applied only to unicellular ani- 

 mal organisms, and among the unicellular vegetable organisms the 

 bacteria have been differentiated from the Palmellacca, the Sac- 

 char omycetes, and the reproductive elements of the higher Alga, all 

 of which were formerly confounded under the general name of 

 Infusoria. 



Ehrenberg (1838) was the first to separate the bacteria as a dis- 

 tinct class of organisms, under the name Vibrioniens ; but he did 

 not include the spherical bacteria — micrococci — in this class, and 

 did not recognize the vegetable nature of these micro-organisms. 

 In his family of Vibrioniens he included four genera, which he de- 

 fined as follows : i. Bacterium (filaments linear and inflexible) ; 2. 

 Vibrio (filaments linear, snake-like, flexible) ; 3. Spirillum (fila- 

 ments spiral, inflexible) ; 4. Spirochate (filaments spiral, flexible). 



Dujardin (1841), in his ' Histoire Naturelle des Zoophytes,' still 

 preserved the family of Vibrioniens of Ehrenberg among the Infu- 

 soria, and it was not until 1859 that the eminent French physician 

 Davaine clearly recognized the bacteria as vegetable organisms 

 nearly allied to the Algs, — a view which was subsequently 

 adopted by the distinguished German botanist Cohn, and which is 

 pretty generally accepted at the present day. Some botanists, 

 however, insist upon the affinities of the bacteria with the micro- 

 scopic fungi, and it is this view which has induced Nageli to de- 

 scribe them under the name of Schizomycctes, or fission fungi. 

 The chief ground for this classification is found in the fact that the 

 bacteria, like the Mucorini, are destitute of chlorophyl. 



The vegetable nature of yeast-cells had previously (1836) been 

 recognized by Cagniard-Latour and by Schwann ; and the vitalis- 

 tic theory, as regards the alcoholic fermentation, was clearly de- 

 fined and established experimentally by the last-mentioned author 

 in 1837. This theorj- was subsequently extended by Pasteur to 

 processes of fermentation and putrefaction in general ; and, in the 

 face of much conservative opposition, the distinguished French 

 savan/ finally demonstrated that in the absence of these living fer- 

 ments organic liquids may be kept indefinitely without undergoing 

 change ; and that contact with the atmosphere does not induce 

 these changes, as had been generally supposed, but that when they 

 follow such contact it is due to the presence in suspension of living 

 micro-organisms. 



Hoffmann ( I S43) had previously shown that calcined air admitted 

 to a boiled organic liquid does not cause putrefaction, and in 1854 

 Schroeder and Von Dusch showed that the suspended particles in 

 the atmosphere may be removed by passing air through a cotton- 

 wool filter. 



For a time the advocates of abiogenesis supposed that they had 



