1887.] MICROSCOPICAL JOURNAL. 153 
pebies: 5 and 6 represent secondary or rosette crystals forming within the 
primary or globose crystals. 
Figs. 7 and 8 represent these secondary or rosette crystals having sepa- 
rated from the primary crystals. The secondaries generally break up into 
stellate forms in the process of decay. 80 to IIo. 
Figs. 9, 10, and 11 represent tertiary crystals, or the third transition stage 
of the butter crystal, generally seen in boiled butter that has been kept sey- 
eral months. 80. to 140. 
Fig. 12 represents tertiary crystals resolving into the ears condition. 
x 140. 
Figs. 13, 14, 15, and 16 represent oleomargarine which has no typical 
form or crystal. 80 to IIo. 
Fig. 17 represents oleo as it generally appears when boiled and cooled. 
XxX 140. 
Fig. 18 represents neutral lard under the same conditions. 140. 
Figs. 19g and 20 represent common lard when boiled and cooled. 140 
to 400. 
- Figs. 21, 22, 23, and 24 represent crystals of beef-fat from v RBIOUS tissues 
of the ox; the omentum, kidney, marrow of femur and round. 65. 
MICROSCOPICAL TECHNIQUE. 
Laboratory Jottings. 
By Dr. GEORGE A. PIERSOL. 
At this time when our American workers are so rapidly appropriating 
and indeed improving, the best methods of present histological technique— 
what a contrast to that of ten years ago—a few reflections suggested by per- 
sonal observation, and endorsed by the usage of some of the most prominent 
of the Continental laboratories, may be pardoned. What follows makes no 
pretence to novelty ; as the teaching of experience it may be of interest. 
The fact is frequently forced home that in spite of all our successful subse- 
quent manipulations sufficient care is not exercised in the preservation of 
material. Where simply relation and arrangement are to be determined, the 
precise condition of the histological elements is of secondary importance ; 
when, however, it becomes a question of cell structure, genesis, or metamor- 
phosis, the value of an entire investigation may depend upon the care and 
accuracy of the initial) proceeding. The distinction between the mere har- 
dening of a tissue and a true fixation of its elements cannot be too strongly 
insisted upon. 
The formerly much valued method of preparing tissues by the successive 
action of 33, 60, 80 and 93 alcohol, while hardening admirably, is now 
admitted to be entirely unreliable for the preservation of fine structural detail. 
That we, as yet, have no reagent, which reliably ‘ fixes’ form and leaves 
protoplasm in a perfectly normal condition examination of many kinds of 
cells will convince every careful observer. 
Of the various ‘ fixing’ reagents offered, upon which can the histologist 
rely for daily use as generally yielding preparations in which the elements are 
well preserved in form and structure?» Our own experience endorses chro- 
mic acid as one of the most reliable and convenient reagents for fixing 
which we possess. 
Its merits are general applicability, reliability, cheapness, ease of prepa- 
