248 
On the Structure and Bevelojpment of 
sisting of single plates, as Eanvier says, tliey are made up of many 
plates, the paddles, wliicli radiate from a centre. In examining 
these tissues with a lens of high power, such as the No. 8 of Hart- 
nack's system, there will be no difficulty in detecting them in every 
instance, and there can be no doubt that the use of haematoxylin 
in these examinations has afforded us the best means of demon- 
strating many points which have previously been obscure. The 
particular reason of the advantage obtained by the use of ha9ma- 
toxylin lies in the fact, that very often it obviates the use of alcohol 
acetic acid, both of which distort the parts, and very often give 
rise to false appearances. It also chiefly affects the plate-like 
bodies and only slightly tinges the delicate envelope, while it wholly 
avoids the rest of the intercellular substance. In this way we are 
able to employ a solution that differentiates the elements most excel- 
lently, in fact far better than carmine, and it is dissolved in water 
and not in acids or alkalies, which have peculiar actions upon all 
tissues. During the latter portion of this work use was often made 
of Hoffmann's violet, which was used as a substitute for the violet 
de Paris or methyaniline (Poirier) recommended by Cornil for 
showing waxy degeneration. It was dissolved in water in about 
the proportion of two grains to the ounce. In half an hour the 
nuclei were beautifully stained of a delicate violet, when the cell 
body and fibres were unaffected. The reaction was much the same 
as haematoxylin in regard to the tissue affected. 
It is with the use of the two reagents that we may get the best 
ideas of the structure of connective substances. 
2. Most of these plate-Hke cells which have often been called 
nuclei are invested by a delicate envelope, the body of the cell. 
This is mentioned by almost all recent observers, and was even 
spoken of by Henle long ago. This substance is seen to advantage 
in the reticular form of tissue (fibrous tissue) already mentioned, 
and is not so deeply stained by hsematoxylin. When the tissue is 
expanded, this sheath or envelope is capable of being drawn out to 
great length, while, when it is separated from its connections, it 
shrinks, assuming the most irregular forms. When the plate-like 
bodies with their envelopes are attached together, they give the 
appearance of "spindle-shaped cells," a name often given to them. 
It may readily be imagined that the changes in form which such 
delicate envelopes assume may be manifold. In moist tissues they 
may swell, and in dry ones they may shrivel. It is the processes 
of such envelopes that often communicate, and the term " netted 
cells " has often been apphed to them. 
The theory developed by Heitzmann* that the connective tissue 
of the umbilical cord, periosteum, and tendons, &c., demonstrates a 
* " Uber das Verlialtniss zwischen Protoplasma und Grimdsubstanz im Thier- 
korper," 'Sitz. d. Wiener Akad. v. und h. JaLiiesbericht,' 1873. 
