SOME FACTORS INFLUENCING THE LONGEVITY OF 
SOIL MICRO-ORGANISMS SUBJECTED TO DESICCA¬ 
TION, WITH SPECIAL REFERENCE TO SOIL SOLU¬ 
TION 
Ward Giltner, Bacteriologist , and H. Virginia Langworthy, Graduate Assistant 
in Bacteriology , Michigan Agricultural Experiment Station 1 
INTRODUCTION 
The following outline is suggestive of the complexity of the problem 
of determining the relative influence of the various factors affecting the 
longevity of microbes subjected to desiccation: 
(1) Properties of the organism which probably depend on species differences. 
(а) Spore formation. 
(б) Capsule formation. 
(c) Peculiarities of cell composition. 
(2) Physiological differences in organisms resulting from treatment before drying* 
(a) Temperature of cultivation. 
( b ) Nutrition. 
(c) Age of culture. 
(d) Virulence and other properties. 
(3) Nature of the medium in which the organism is suspended before drying. 
(а) Its possible plasmolyzing effect. 
(б) Its content of protective or water-retaining substance. 
(4) Physical structure of the substratum upon which drying occurs. 
(a) Smooth, nonabsorbent surfaces. 
(b) Textile fibers or fabrics. 
(c) Soil, etc. 
(5) Effect of physical agencies. 
(a) Light. 
(1 b ) Temperature. 
(c) Variations in humidity, etc. 
Only a few of the points in this outline will be treated in detail in this 
paper. 
HISTORICAL REVIEW 
A review of the literature reveals only the facts that are usually incor¬ 
porated in recent text books on microbiology. The longevity of spores 
is too well known to demand discussion at this time. It is recognized in 
the literature that the presence of a gelatinous capsule is an excellent 
means of protection against adverse circumstances, especially desicca¬ 
tion. It is also noted by Eiesenberg and Zopf (13) 2 that with an organism 
1 This paper represents part of a piece of work planned and prepared for publication by the senior author, 
but executed almost entirely by the junior author as a part of the requirements for the degree of Master of 
Science. 
2 Reference is made by number to "Literature cited,” p. 941-942. 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
cj 
(927) 
Vol.V, No. so 
Feb. 14,1916 
Mich.—4 
