AGRICULTURAL BACTERIOLOGY 



CHAPTER I. 

 INTRODUCTION. 



I. TAKE some hay and chop it into short pieces about 



an inch long. Then place it in a glass beaker or cup, 



pour cold water over it, and 



leave in a warm room for a 



day or two. The cold water 



dissolves various substances 



from the hay and becomes 



brownish in colour, rather like 



weak tea. If a drop of the 



solution is taken from the 



cup or beaker and examined 



with a microscope, many 



living things will be found FlG .,_ Drop of ha y infusion . * Protozoa; 



swimming about in it. Fig. I 



gives the appearance of what is generally seen in such 



a drop examined under a moderate magnification (an 



ordinary microscope with a f objective). The most 



obvious living beings are small oval transparent organisms 



which glide in all directions across the field of view 



(Fig. i, a). Sometimes there are few of them, but in the 



majority of trials with a hay infusion they will be met 



