1890.] MICROSCOPICAL JOURNAL. 133 



If, as the tlieory of evolution presupposes, that there is really no such 

 thing as a distinct species — a species being only a stepping-stone be- 

 tween a lower and a higher organism, in its upward progress of devel- 

 opment — we should lind in these minute organisms transitional forms 

 shading into each other on every side. But as our knowledge becomes 

 more complete of these organisms, we find that this is not the case. 

 In fact, we find just as distinct morphological characteristics in the lower 

 organisms as in the higher classes of animals. Over one hundred spe- 

 cies of micro-organisms are now said to be known, which either 

 cause or find their appropriate habitat in pathological conditions exist- 

 ing in man and the higher classes of animals. Many of these have been 

 so thoroughly studied that we know their life-history just as accurately 

 as we know that of the lion of Africa or the elephant of India. 



When a biologist sows witli proper precautious a pure culture of 

 bacillus anthracis (The Bacillus of Anthrax or Charbon), does he ever 

 get a progeny of bacillus tul)erculosis.^ Or if he plants the germs of 

 bacillus tuberculosis, does he ever pioduce the straphyloccus poyogenes 

 aureus (or organism which causes the forinati(Mi of pus) .^ Most as- 

 suredly not. 



It is perfectly true that, h\ the microscope alone, it is ditlicult and 

 sometimes impossible to distinguish between the different forms of 

 micro-organisms. Each, however, can be identified in some w^ay, 

 either by its color, or form, or habitat, or method of growth. One 

 micro-organism thrives in bouillon, another in gelatine, another in 

 agar agar ; one grows in small colonies of germs, another in single 

 rows • some liquef\- the gelatine or agar agar in which they grow, 

 others do not. The more we study these minute organisms the more 

 we are struck by their characteristic differences from each other. No 

 more striking exemplification can be given of the value to mankind of 

 scientific facts than is pi"esented in the growth and development of the 

 modern aseptic or, as it is often called, the Lister method of surgery. 



The discoverer of the fact that certain minute organisms almost 

 always found in the atmosphere, and which by their presence produce 

 pus and septic poisoning, could scarcely have ever imagined the grand 

 consequences and l)lessings to mankind that would result from it. By 

 excluding from wounds and injuries these poisonous germs, surgery in 

 our day has been completely transformed, and the gravest operations of 

 surgery robbed of almost all of their terrors. One operator, Mr. Law- 

 son Tait, of England, has operated for the removal of tumors from the 

 abdomen over two thousand (3,000) times, and with a mortality that 

 is steadily diminishing. In this last series of one thousand cases he 

 reports an average mortality of 5^^ per cent. — in other words he has 

 succeeded in saving from certain death nearly ninety-five (95) out of 

 one hundred (100) persons operated upon by him. This whole super- 

 structure of modern surgery is built upon tlie laws controlling the 

 growth of micro-organisms, and their unchanging methods of devel- 

 opment. 



Probably the most l)cneficent gift that the science of medicine ever 

 gave to mankind was Dr. Tenner's great discovery of vaccination as a 

 preventative of small-pox. During jiast centuries small-pox spared no 

 rank or station in society, from the monarch in his kingly robes, to the 

 beggar in his rags; all felt the power and virulence of this dread dc- 



