260 STATE HORTICULTURAL SOCIETY. 



maturity, decay, and systematic death. Death is a concomitant of life. 

 During the growth and activity of the organism, molecular death is constantly 

 taking place as an essential part of the process of nutrition, and systematic 

 death occurs at the close of the cycle of living activities. 



5. There is likewise a differentiation of the protoplasm of living beings into 

 organs for the efficient performance of various functions, but this is more 

 marked in the higher and more complex forms. 



(3. Its mode of growth is peculiar, the addition of new materials is interstitial, 

 and not by external accretion. 



7. Keproduction, or a provision for the perpetuity of the species, is one of 

 the most striking characteristics of living matter. 



On the other hand, non-living matter is characterized by its simple chemical 

 composition. Its increase in size is not an interstitial growth, but by external 

 accretion, and it is subject to the ordinary disintegrating agencies, as oxida- 

 tion. In a word, it lacks all the peculiarities enumerated as characteristics of 

 living matter. 



From this outline of its characteristics, it will be seen that living matter in 

 its simplest, as well as in its most complex forms, must be able to carry on the 

 process of nutrition, which involves the subordinate functions of prehension, 

 digestion, assimilation, respiration, and excretion, and it must provide for a 

 continuance of the species by the function of reproduction. Now, in all the 

 simplest forms of life, these processes are carried on by the nearly homogeneous 

 protoplasm of which they are composed, while special organs for the perform- 

 ance of each function are developed in the higher. 



In the lowest forms we have motion and what seems to be closely allied to 

 sensation, and we observe resting phases in their existence which remind us of 

 sleep in the higher animals. 



The physiological activities of living matter are only manifested under 

 certain favorable conditions of temperature, moisture and food supply; and a 

 wide range of variation in each of these particulars will be required to secure 

 the best possible provisions for the growth and development of the different 

 species. When the prescribed conditions are best adapted to the wants of one 

 species, others, from a difference in their vital activities, will not be as well 

 provided for, and they cannot therefore successfully compete with the more- 

 favored form in the battle of life. 



It is a popular notion that microscopic forms of life are ubiquitous, and 

 that almost every variety may be found under all possible conditions. An 

 intimate acquaintance with the life history and habits of a number of species 

 will, however, show that the competition of these minute beings in " the 

 struggle for existence " is quite as severe and well marked as in those higher 

 in the scale of organization, and it will readily be seen that we can promote 

 the development of desirable forms, and keep in check those which are detri- 

 mental by controlling the conditions in which they are placed. 



The ordinary samples of commercial yeast, when examined under the micro- 

 scope, will be found to contain three or four, or more, species of organisms, 

 only one of which is a true ferment. When the yeast is used under conditions 

 that are decidedly favorable for the rapid increase of this desirable form, an 

 active fermentation takes place ; but when the species that are not true 

 ferments are favored by temperature, degree of moisture, or supply of nutritive 

 materials, there is a failure in the process of fermentation. 



Pasteur made the discovery that the so-called diseases of beer and wine were 



