256 
MR. SAVORY ON THE DEVELOPMENT OF 
weak acids, which is recommended for the purpose of bringing the nuelei into view, 
always affects their appearance by altering their shape to an extent proportioned to 
the strength of the re-agents. They shrink, their outline becomes more or less 
disturbed, and they appear shrivelled ; hence many of the descriptions and drawings 
of these nuclei are unfaithful. An artificial appearance, the effeet of re-agents, is 
described and figured as the natural one. 
However much the shape and other characters of these nuelei may be affected by 
various re-agents, they are not easily destroyed. When muscular tissue is preserved 
in alcohol, they shrink, but remain for a longtime; at last, however, they become in- 
distinct, they appear like large and irregular oil-globules, and finally break up. By 
the prolonged action of sulphuric ether, the nuclei become irregular in outline and 
somewhat shrivelled, and their substance presents a uniform clear and glistening 
appearance. 
These and similar effects appear in great measure due to time, and this ultimate 
disintegration of the nuclei, under almost all circumstances, is the chief obstacle to 
the preservation of foetal muscular fibre ; but generally, as the nuelei become altered, 
the whole structure of the fibre undergoes a change. The strise, when they exist, 
become confused and then disappear, and the interior of the fibre is occupied by 
globules of different size, closely resembling globules of oil. 
Explanation of the Plates. 
PLATES X. and XL 
Fig. 1. Cytoblasts from the tissue of the dorsal region of a foetal pig, 1 inch in length. 
Fig. 2. Portion of muscular fibres from a foetal pig, between 1 and 2 inches in length. 
The first stage in the formation of muscular fibre. 
Fig. 3. Muscular fibre from a foetal pig, between 2 and 3 inches long, showing the 
linear arrangement of the nuclei and narrow bands. 
Fig. 4. A similar specimen. The nuclei at one extremity have not fallen into their 
places, and the lateral bands are separated to a corresponding extent. 
Fig. 5. Fibre from a foetal pig, 3^ inches long. Lateral bands increasing in width. 
Breadth of fibre jT^th of an inch. 
Fig. 6 a. Fibres from the upper extremity of the leg of a Tipula. 
Fig. 6 b. Fibres from the upper extremity of the leg of a blue bottle fly {Musca 
vomitoria ) . 
Fig. 7. Fibre from a foetal pig, 3 inches long, showing separation of the nuclei. 
Fig. 8 a. Fibre from a foetal pig, inches long, showing the progress of develop- 
ment in different portions. Breadth of fibre, where the nuclei are in con- 
tact, xwoth of an inch ; where nuclei are ywoth of an inch apart, breadth 
of fibre ^5-0 oth of an inch. 
This fibre floated freely in the field. 
