1890.] MIOROSCOriCAL JOIJUNAL. 131 



The Life-History of Mi(ro-Ori;:iiiisms, with its llehitioii to the 

 Theory of Evolution.* 



By ROBERT REYBURN, M. D., 



PROF. l'HYSIOI-0(iV ANI> CLINKAI. SHUGEKY IN HOWARD UNIVEHSITY, WASHINGTON, D. C. 



It is the (listinguishinjT characteristic of a hitherto unknown hiw of 

 nature, that it l:»rings into harmony and order many isolated tacts that 

 before its discovery seemed to have no connection with each other. 

 Such a hiw of nature, to the great majority of the scientists of the pres- 

 ent day, the theory of evolution has seemed to he. There is a dazzling 

 simplicity in this hypothesis of the genesis of all organic forms that is 

 very attractive to the imagination. To believe that all living organized 

 existences have been produced from a few masses or particles of living 

 protoplasm, by the forces of natural selection and the conditions of their 

 environment, is indeed solving the mystery of the universe as easily as 

 a child, I)y the aid of the letters of the alphabet, masters the words of 

 his mother-tongue. 



But when in a spirit of calm and scienti'fic inquiry we proceed to 

 study these problems, we do not find them quite so eas\' of solution as 

 the theory of evolution would seem to indicate. Difficulties and doubts 

 arise that must be overcome before we can accept it. 



The life-history of micro-organisms shoidd throw light on these 

 questions ; many of them are composed of small particles of germinal 

 matter, or protoplasm, without either the nuclei, cell walls, or cell con- 

 tents, that are found in what are ordinarily known as cells in living 

 organisms. Before our eyes and on the stages of our microscopes, we 

 can study them to our hearts' content. We can watch them multiply 

 either by the development of ova (or eggs), by gemmation (or bud- 

 ding) , by fission (or division) , or by the production of alternate or suc- 

 cessive generations. 



The first question to be answered concerning these microscopic or- 

 ganisms is the natural query, Whence came they.'' To this question 

 evolution gives no answer. 



Just as impassable as it was before the invention of the microscope 

 is the yawning gulf that divides living protoplasm from dead matter. 

 We can start on our argument to-day with the axiom, Omnia vivuin 

 ex ovo (every living thing has sprung from an e^'g or germ), with just 

 as much assurance of its truth as when it was first enunciated by the 

 great philosopher. Yea, even more so, for time and increased knowl- 

 edge have only accimiulated evidences of its truth. 



When the biologist of to-day makes a pure culture of a living organ- 

 ism, and places it with the proper precautions, in a pine medium or 

 soil fitted for its growth, he .invariably finds, and expects to find, the 

 same organism growing under his eyes, or on the stage of his micro- 

 scope. He no more finds, or expects to find, a different organism 

 resulting, than a horticulturist would find grapes growing upon an apple 

 tree or thistles upon a plum tree. In regard to the theory of sponta- 

 neous generation, or the spontaneous formation of living organisms, 

 from dead matter, it is only necessary here to say, that it is almost 

 universally abandoned by all biologists of any eminence. This theory 



* Read before the Washington Microscopical Society, April 8, 1890. 



