174 BOAUI) OK AOKIOn.TIKK. 



a[)|)Ctiianee of the ctii)sule has I>een chiiiiKMl to I>l* (HagiiOHtic. Imt 

 wh«'n present its color is not alone snflicient to distinguish it from 

 the surrounding tissues, luiless ealcitled If the muscle is quite red, 

 however, triciiina* are verv liable to l)e present. 



Accordingly the microscope is our only means of determining their 

 presence beyond a doubt. This investigation is l)est made during 

 life, by harpooning a piece of muscle for the purpose, and the regions 

 of the neck, shoulders, and fore-limbs seem to have the preference. 

 But in the dead animal. Leuckart has found the diaphragm to con- 

 tain the largest number of young trichiiuv, and the tenderloin, larynx, 

 and tongue are also easily accessible to these wandering parasites. 



In severe cases of infection the muscles of the posterior extremi- 

 ties arc also found to contain them, but when trichinae cannot be 

 found in the anterior parts it is useless to look for them in the hind 

 legs. Trichin.e are frequently' more abundant at the extremities of 

 the long muscles than in the central portions, consequently these 

 parts should be chosen for examination 



To get the best view of the encapsuled worm, lay bare the fibers 

 by separating them from the surrounding connections. Take up a 

 small portion with the forceps and thus separate in the direction of 

 the fibers a portion of tissue not more than a millimeter (.03 ot an 

 inch) in thickness. Avoid the blood vessels and nerve filaments, 

 and select a sample near the tendon, as the trichinae are most abun- 

 dant in that portion. Place the specimen on a glass slide and with 

 mounted needles spread it out to double its width. Moisten the slip 

 with a solution of caustic potash, sa^'s Leuckart, and after a few 

 moments, when the muscle becomes clear, lay on a cover of thin 

 glass, flatten out the sample, under pressure, and remove the air- 

 bubbles. By holding the specimen now towards the light, capsules 

 can be seen by the naked eye, as small, clear specks. 



These parasites vary in appearance, according to their age and 

 degree of development, but their absence cannot be relied upon from 

 the results of a single specimen examined. When the cj'sts are cal- 

 cified they can readily be seen by the unaided eye, as little white 

 points in the muscular tissue. 



In all such microscopic examinations of infected meat great care 

 should be taken to have the glass slips and covers free from all for- 

 eign substances, specks, etc., which have so often been mistaken 

 and confounded with the object in question. 



