QUARTERLY CHRONICLE OF MICROSCOPICAL SCIENCE. 183 
fluid, and undergo this or that metamorphosis. The author 
met with many failures, and recommends the following 
method. Small plates of glass must be used, 10 to 20 
millimétres (0°04 to 0:08 inch) long and 10 millimetres (0°4 
inch) broad. Large ones easily occasion profuse suppura- 
tion. The plates were generally left from ten to twenty-five 
days in the spot operated on. The best field for operating 
is the inner side of the thigh of not too old dogs. Rabbits 
gave no satisfactory results. After the plates were removed 
they were slightly washed, and at once placed in a 1 per 
cent. solution of perosmic acid, and allowed to remain there 
for two days. They were then placed in spirit with glycerine, 
then in pure glycerine. 
The following were the results of sixty-five experiments. 
An in-wandering of colourless blood-corpuscles took place 
in all cases. The changes of the same in the first ten days 
varied according to the direction of the development. After 
several days, a flattening of the corpuscles and the formation 
of a cellular mosaic were often to be observed. After this 
time the author found :— 
In the greater number of cases only retrogressive changes, 
but in some cases progressive processes showing different 
developmental directions, viz. :— 
la. The Formation ofa Retictlar Tissue with Enclosed 
Epithelioid Cells and Rich Development of Giant Cells.— 
This is, without doubt, the most interesting result. The 
giant cells consist of finely granular protoplasm and certain 
numerous large oval nuclei and distinct nucleoli, sometimes 
with round sharp contours, at others provided with processes. 
It can be seen, in one and the same microscopical prepara- 
tion, how they are developed from the colourless blood- 
corpuscles by increase of the protoplasm and simultaneous 
increase of the nucleus, till they reach the dimensions of the 
largest known giant-cells. 
b. Developmentof Connective Tissues and Vessels.—Similar 
appearances to those of developing connective tissue were 
found. As the first stage in the development of the vessels 
there is clearly observed a network of peculiarly changed 
colourless blood - corpuscles ranged one on _ another, 
which increase considerably on the surface, and are firmly 
fixed on the edges, and gradually assume an epithelioid 
character. ‘The author draws the following conclusions :— 
ce. Real giant-cells can develop from colourless cor- 
puscles. 
Under similar conditions, cytogenous connective tissue 
with epithelioid cells is formed. 
