486 
Max Morse 
spermatogonia or oügouia tu the spermatozoa or mature eggs. As a 
rule, a siugle testis will give such a continuous liistory, one follicle 
coutainiug cells iu a giveu stage, while adjoining follicles contain 
earlier or later ones and indeed, in some cases, within a giveu cyst, 
one may lind cells giving a continuous history over the greater part 
of one of the sperinatocyte stages. Such cases render the Inter- 
pretation of the sequence of events certain. 
The testes 1 ) were dissected out in Ringer’s solution and trans- 
ferred at once to the fixing agent. These fixatives are as follows, 
arranged in Order of importance in the opiuiou of the writer: 
Flemming’s stronger fluid, Bouix’s fluid, Tellyesniczky’s fluid, Her- 
mann’s fluid, Gilsox’s fluid, sublimat-acetic and corrosive Sublimat 
(HgCl 2 ). The best results in general were obtained from Flemming 
preparations. Before Auerbach’s (‘96, p. 414) valuable stain, it is 
necessary to use a fixative containing HgCl 2 , the most satisfactory 
of which has proven to be the solution of Gilsox. Some of the 
very best preparations were obtained from Tellyesniczky’s fluid. 
The following stains were employed; Heidenhain's iron-hema- 
toxylin, used alone or counterstained with congo red, eosin, acid 
fuchsin, alum carmiu, or Orange G. Zwaardemaker’s safranin, used 
alone or counterstained with Lichtgrün. Auerbach’s modification of 
the Ehrlich -Biondi stain. Thionin. Flemming’s Triple Method. 
Gross’s alum-carmin Bleu de Lyon method. Delafield’s hematoxylin, 
with counterstains of congo red or eosin. For the preparation of 
smears, Bismarck Brown was used regressively. 
The smears were made by pricking the cyst and allowing the con- 
tents to flow out evenly on the slide where they were permitted to 
dry, alter which they were stained. Living cells were examined as 
Wilson has done by openir.g a cyst into a drop of Ringer s solution 
and studying the cells with oil immersion without staiuing. 
Auerbach’s method has been fouud most useful as 2 ) a ditfereu- 
tial stain for chromatin and plastin structures. It is true that the 
stain ncver gives sharp outlines to the cell elements and that one 
may so time the exposure of the tissue to the stain as to obtain all 
of the cell components colored with the fuchsin or all stained with 
the methyl green, in which case, of course, uo distinction between 
1 For the anatoiuy of the sex organs of Periplaneta , one may refer to 
Miall and Denny (’86j. 
2 j See Heidenhain ’07. 
