12 THE MICROSCOPE. 
Dr. Gregg has been very kind and courteous in showing the com- 
mittee his objects and apparatus, in explaining to us his methods 
and the salient points of his paper, for which we take this oBpot 
tunity for expressing our appreciation and thanks. 
Perhaps it is a work of supererogation to remark in the pres- 
ence of this club that one untrained in the use of the microscope 
cannot form a definite opinion or just conclusion concerning this 
or any other matter of investigation with the microscope, until 
made acquainted with the character of the instrument employed 
and the methods of research pursued. Especially is this true in the 
study of the minute objects regarded as bacteria, whatever may be 
their nature. We will, then, first refer to the Doctor’s apparatus 
and his methods of examining objects. 
The observations detailed in the paper were made with a Bausch 
and Lomb “Model” stand, “professional” one fourth inch objective 
of r1o° angular aperture, and one and one-third inch Huyghenian 
eye-piece; the combination gives about three hundred diameters. 
The objective appears to bea fairly good one of its grade. The 
illumination employed was light from a centrally placed mirrors di- 
rect and diffuse sunlight without the use of a diaphragm is a favor- 
ite method of illumination with Dr. Gregg. He studies his objects 
dry, without cover-glass! Any worker with the microscope will un- 
derstand how much allowance must be made,for errors that are sure 
to occur in this method of examination. In preparing a slide of 
“bacteria” for study he proceeds thus: The material—blood or 
fibrine, whether fresh, boiled or rotting—is taken from its recepta- 
cle with a stick and gently drawn across a glass-slip, after which it 
is allowed to dry, either at the ordinary temperature of the room or 
it is more quickly dried by means of heat. The preparation is then 
examined after the manner mentioned above, when the various 
forms or appearances of the “bacterists’” arise. ‘Is it remarkable 
that he sees all, and more of the bacteria of the catalogue? We 
think not. Nor is there any wonder that he exclaims on thus ex- 
amining blood boiled for an hour, “all the forms that the ‘ bacter- 
ists’ ever pictured or saw, in their bacteria, are exactly represented 
in boiled blood; and there are many more forms found than they 
have ever mentioned.” 
“There are the so-called micrococci by the million; there are 
spherical bacteria ‘aggregated in pairs and in fours,’ or in any other 
