STAINS, ETC. 



1406 



STANDSTILL 



are fixed in their natural forms, and the nuclear struc- 

 tures clearly brought out by the picrocarmin. Larvae of 

 Echinodermata. Pluteus larvae are placed for 2 or 3 

 minutes in a cold, saturated solution of corrosive subli- 

 mate, then washed in water and stained with Mayer's 

 cochineal (see Staining Reagents). The stain should be 

 diluted so as to possess a barely perceptible tinge of 

 color, and the objects left in it from 12 to 24 hours. 

 They are then mounted in balsam or oil of cloves (Bar- 

 rios). This method is equally applicable to other forms. 

 Medusae. Van Beneden's Method. This consists in 

 pouring glacial acetic acid over the organisms, and after 

 5 or 6 minutes washing them in alcohol, changing it 

 frequently, and gradually increasing its strength. It is 

 said that the tentacles may be kept from rolling up by 

 imparting a swirling motion to the fixing fluid, putting 

 in but one medusa at a time, and keeping up the vortex 

 motion until the animal is fixed. The Heriwigs 1 

 Method. For the study of the nervous system. The 

 organisms are treated with a mixture of equal parts of 

 O.05 per cent, osmic acid and 0.2 per cent, acetic acid, 

 and after 2 or 3 minutes washed in O.I per cent, 

 acetic acid until every trace of osmic acid is removed. 

 They are then placed in o. 1 per cent, acetic acid for 

 24 hours, washed in water, stained with Beale's carmin, 

 and mounted in glycerin. Nerve and Muscle of 

 Arthropods. Place a number of Milnesium tarai 

 gradum in a test-tube containing water from which the 

 air has been expelled by boiling. Cover the surface of 

 the water with a drop of oil, so as to exclude the air. 

 After 24 hours or more the animals will be found fixed 

 and extended in a cataleptic state, and they can then be 

 examined in boiled water. They are quite transparent 

 in this condition, and the nervous and muscular systems 

 stand out distinctly. Porifera. Small sponges may 

 be fixed by the usual reagents, preferably by osmic acid, 

 and should be immediately transferred to absolute 

 alcohol and stained with an alcoholic solution— Mayer's 

 cochineal solution is recommended (see Staining 

 Reagents). Sections may be made by decalcifying in 

 alcohol acidified with hydrochloric acid, and then 

 embedding in paraffin in the usual way. Rotifers. The 

 living animal may be examined after quieting with warm 

 water or a 2 per cent, solution of cocain hydrochlorate. 

 For permanent preservation Rousselet recommends 

 the following process. Place the animals in a trough 

 containing water, and narcotize them by adding cocain 

 of 1 or 2 per cent, strength ; watch them under the 

 microscope until the cilia cease to vibrate, and then 

 fix them in Flemming's strong solution, which should 

 be introduced into the trough by means of a pipet. 

 After 15 minutes wash them in several changes of 

 distilled water, and mount in distilled water containing 

 a little Flemming's solution, about 8 drops to 30 c.c. of 

 water. Sarcolemma of Insects. To demonstrate 

 the two lamellae of the sarcolemma, digest muscle of 

 an insect in artificial gastric juice for from ^ to 

 I hour, at the temperature of the room in summer, 

 and examine in gastric juice. Siphonophora. 

 Bedof s Method. Add to the sea-water containing the 

 animals a considerable quantity of from 15 to 20 per 

 cent, solution of copper sulphate ; this fixes them in a 

 few minutes. Add a few drops of nitric acid, and after 

 from 4 to 5 hours add Flemming's solution in the 

 proportion of 2 parts to I of the sulphate solution. 

 After 24 hours, a few drops of a 25 per cent, alcohol are 

 introduced by means of a pipet in such a manner as 

 to disturb the colony as little as possible ; alcohol of 

 gradually increasing strength, up to 70 per cent., is 

 cautiously added during the next 14 days, and 90 per 

 cent, alcohol is used for preservation. This method has 

 the advantage of preserving the specimens with all 



their swimming-bells and polyps in situ. Trematodes. 

 Bisher's Alethod. These forms may be preserved 

 entire as follows : Treat Opiuhoti-ema cochleare with 

 absolute alcohol, then stain with hematoxylin or picro- 

 carmin, clear in clove-oil, and mount in balsa.-n. 

 Trichinae. Examination of the living parasite. 

 Place a piece of trichinized muscle about the size of a 

 cherry-stone in a bottle containing 3 gr. of pepsin, 2 

 dr. of water, and 2 drops of hydrochloric acid ; keep 

 at 98 F. for about 3 hours, shaking occasionally. 

 When the flesh and cysts are dissolved, pour the fluid 

 into a conical glass and let it settle. The trichina? 

 are then drawn off with a pipet, placed on a slide 

 with water, and examined on a warm stage (Barnes). 

 Stalaxis {stal-ahs'-is). Synonym of Staxis. 

 Stalk {stawk) [ME., stalken\. Any lengthened sup- 

 port to an organ . 

 Stallion [stal'-yon) [ME., stalyone, stallion]. The 



male of the horse. 

 Stamen {sta' '-men) [orr/fiuv, a thread as spun, the warp 

 in the loom : pi. , Stamens']. In biology, the pollen- 

 bearing organ of the flower, when complete con- 

 sisting of a stalk or filament and a pollen-sac or anther. 

 Stamina {stam' -in-ah) \_ari]iiuv'\. Natural strength 



of constitution. Vigor. Inherent force. 

 Staminal [stam'-in-al) [ottjuuv, a thread]. Pertaining 



to a stamen. 

 Staminate {stain' -in-at) [cttj/iuv, a thread]. Possi 

 stamens. Applied to flowers which have stamens 

 but not pistils. 

 Staminidium (stam-in-id f -e-nt>i) [orr/fiuv, a thread: 



pi. , Staminidial. An Antheridium. 

 Staminiferous {stam-in-if'-er-us) [ottjliuv, a thread ; 



ferre, to bear]. Bearing stamens. 

 Staminigerous {slam-in-if '-er-us) . Same as Staminif- 

 erous. 

 Staminode {stain' '-in-dd) . Same as Staminodium. 

 Staminodium {stam-in-o' '-de-um) [gt?//iuv, a thread ; 

 e)6or, form]. In biology, a stamen like organ ; a 

 rudimentary or aborted stamen; a parasternal! . 

 Lepal. 

 Staminody {slam' '-in- o-de) [ornjuuv, a thread; 

 form]. In biology, the conversion of various organs 

 of a flower into stamens. 

 Stammer {stani'-er) [ME., stameren, to stammer]. To 

 utter with hesitation. To articulate only after repeated 

 attempts ; to stutter. In a wider sense, any speech- 1 

 disturbance is called a stammer. 

 Stammers' Cell. See Cell. 



Stanch {stanch, or stawnch) [ME.,sA»/«<7^', stanch].; 

 To check or stop (a flow) ; as to stanch a hemor- 

 rhage or a wound. 

 Stand [ME., standen, to stand]. To have an upright, 

 posture. Also, a frame or a table to place things 

 upon. S., Microscope, the tripod or base ol the 

 microscope with the tube, but without eye-pieu 

 objectives. 

 Standard {stan'-dard) [ME., standard; extender*, tc\ 

 spread out]. An established rule or model. A cri- 

 terion for comparison. See Ve.xitlum. 

 Standardization {stan-dar-diz-a'-shun) [ME. , standard | 

 standard]. Regulation by a standard; conformity t( 

 or use as a standard of comparison ; the bringil 

 a preparation up to a definite standard. 

 Standstill {stand' -stil) [Ml-:., $t<uid,-n> to stand ; Ml 

 stille, still]. A state of quiescence dependent 

 suspended action. S., Expiratory, suspensii 

 action at the end of expiration. S., Inspiratory, ij 

 halt in the respiratory cycle at the end ol 

 when the lungs are filled with air. Tin 

 can be produced by stimulating the central end 

 cut vagus. S., Respiratory, suspended respin 



