698 Journal of Agricultural Research vol. vi.no. 18 



The improvement of the present situation is obvious. As the full life 

 cycle of probably every species of bacteria can be studied without diffi- 

 culty within a few weeks, provided suitable media are known and used 

 for the experiment, we may hope that the time of reckless species-making 

 will soon be ended. As said before, "good" species will win very much 

 by such renewed and thorough study. The innumerable others, how- 

 ever, will have to take their modest place as links in those life cycles to 

 which they really belong, or they will have to be canceled entirely. That 

 the discovery of the conjunct and symplastic stage and further experi- 

 mental studies upon it are of fundamental importance for reaching cor- 

 rect conclusions concerning species or varieties is beyond question. 



Undoubtedly all our physiological studies will gain in much needed 

 conformity and accuracy when established on the new broad morpho- 

 logical basis. It is to be hoped that such investigations now will also 

 meet with more interest in botanical laboratories, where many of the 

 general problems in bacteriology should be studied, as usually the time 

 of agricultural and medical bacteriologists is complete^ taken up by 

 their more specialized work. For instance, those curious but heretofore 

 entirely unexplainable regular seasonal variations in the activity of bac- 

 teria in soils, quite frequently observed in Europe as well as in America 

 during the last years, now seem to become explainable as a result of the 

 seasonal effect upon the different modes of multiplication and propaga- 

 tion of the bacteria. A similar dependency on this factor then would 

 exist as with other organisms. At least we can hardly consider it being 

 merely an accidental coincidence that essentially the same annual curve, 

 showing a maximum in spring and another one in autumn, is also fol- 

 lowed by lower fresh-water algae, where, as Transeau's careful investiga- 

 tions (20) have shown, the temporary prevalence of spore formation and 

 of vegetative processes apparently represents the principal cause of these 

 variations. 



Concerning pathological problems, we readily admit that we are entirely 

 laymen. However, we feel sure that this branch of bacteriology also 

 would win considerably b)^ making use of our observations. They show 

 that Henri's (10) very interesting results obtained with B. anthracis could 

 easily be duplicated with this or other pathogenic species simply by 

 studying the relation of virulence and type of growth. That those ab- 

 normal looking and abnormally reacting forms obtained by the French 

 author by the application of ultra-violet rays are nothing else than some 

 of the regular though heretofore unknown types of growth of B. anthracis 

 needs hardly be emphasized. Investigations upon the relations existing 

 between pathogenic and nonpathogenic bacteria, as well as the experi- 

 mental transformation of one type into the other, now undoubtedly be- 

 come much more accessible and promising. The same holds true con- 

 cerning the filterable vira. At least some of them are surely to be ex- 

 plained as nothing else than filterable gonidia of well-known bacteria. 



