The Microscope. 75 



to go OTer it twice; time is thus saved, and they get through 

 work an hour earlier than they otherwise could. As near as I 

 can estimate there is a gain, for the same effectiveness of work, 

 of fully a quarter the time. I could, in fact, get along with two 

 less assistants and still have a surplus for emergencies caused by 

 illness, or by an extra number of samples to be inspected, for at 

 one of the abattoirs we inspect all they slaughter. It is more 

 important, however, to increase the eflSciency of the operators 

 than to economize by lessening the number employed. 



That which especially directed my attention to the need ©f 

 such mechanical help in the search, was the fact that not infre- 

 quently slides would be passed to me for verification, in which I 

 found great difficulty in rediscovering the parasites in cases when 

 only one or two were present. It is not unusual for pieces got 

 a second time from the animal to show no Trichinae until several 

 preparations have been made. These facts show that Trichinae 

 may easily be overlooked, or not be present at all in the first 

 preparation made, even though the slide be covered with fibre 

 taken from those parts of the animal most profusely infested^ 

 In view of this practical value of my device I was urged to pat. 

 ent it, and did make application, but I withdrew it on finding 

 that it would be apt to prejudice the Bureau officials against the 

 general adoption of the device. It is now free for any one to 

 use or improve upon, and I trust some such plan will soon be 

 introduced at all the Government stations. Mr. W. T. Johnson, 

 of the above named Electric Service Co., has an idea of a me- 

 chanical stage, which, though more expensive, would be better, 

 namely, to impart to the slide carrier a special motion starting 

 from the centre, and regulated to cover all the field, with a rap- 

 idity dependent on the power used and the will of the operator. 

 Such a piece of mechanism, he thinks, could be furnished in 

 quantity for five or six dollars each, and it would require a dif- 

 ferent shaped slide from that now in use. If making a frame 

 myself to carry the slides I should have simple springs on the 

 sides to hold them in place, with a ledge to rest against on one 

 side. I have modified the compresser frame by adding such a 

 ledge strip to the bottom piece and, taking off" the top piece, had 

 brass washers soldered to the little screw nuts, using these to 

 keep the slide in place. Nothing more is requisite, and this 

 allows quick adjustment. 



