528 



SUMMARY OF CUKRENT RESEARCHES RELATING TO 



proboscis and antennae, and they do not, as a rule, require to be touched. 

 Put the specimen on one side to harden, and then chip off excess of 

 Canada balsam, place the glass ring on, and fill up the chamber that is 

 thus formed with Canada balsam. The upper surface of the Canada 

 balsam should be convex, so that when the cover-glass is applied no air 

 bubbles are included. Allow the specimen to harden before sending by 

 post. If glass rings . are not at hand, the specimen will keep quite 

 well in the Canada balsam alone, and the last part of the mounting may 

 be completed after the specimen has been sent home. If the mosquito 

 is intended for photographing, great care must be taken in mounting it 

 so that it lies as far as possible in one plane. 



Fig. 144. 



6) Miscellaneous. 



Simple Apparatus for filling Gelatin Tubes.* — Dr. E. J. Petri 

 uses the following simple and inexpensive apparatus (fig. 144) for filling 

 test-tubes with gelatin. An ordinary laboratory stand with a ring about 

 12 cm. in diameter supports a funnel which contains 

 the liquefied gelatin heated to about 80°-90°. The 

 top is covered with a cap or glass plate. To the pipe 

 of the funnel is fitted a piece of rubber tubing closed 

 by a stopcock. Into the lower end of the tubing fits 

 a glass tube the free extremity of which is somewhat 

 pointed. This tube is passed through a cork stopper. 

 The stopper has a second perforation for a short bent 

 tube which is stuffed with cotton- wool. The stopper 

 fits into a glass tube or a test-tube the lower end 

 of which is melted off in the flame so as to leave a 

 round smooth hole. A small strip of paper is then 

 stuck on the tube to indicate 10 ccm. The mani- 

 pulation of the apparatus is very simple. The funnel 

 is filled with fluid gelatin. The tube is taken in the 

 left hand and the aperture closed with the thumb. 

 With the right hand the stopcock is opened and gela- 

 tin allowed to flow in up to the paj)er mark. A test- 

 tube is now taken up in the right hand and the cotton- 

 wool plug removed by the 4th and 5th fingers of the 

 left hand. The tube is then placed under the open- 

 ing and the thumb removed so that the gelatin flows 

 in. The cotton-wool plug is then replaced. In this way dozens of 

 test-tubes are easily filled. 



New Quantitative Method for Serum Diagnosis, f — Dr. R. T. 

 Hewlett and Mr. S. Rowland describe a new quantitative method for 

 obtaining accurate dilutions of serum or blood. 



Ordinary vaccine tubes are taken, the large, the very small, and any 

 irregular ones being discarded, those preferred varying in diameter from 

 about O'O-l^ mm. They are boiled in strong nitric acid, thoroughly 



* 



* Centralbl. Bakt. u. Par., xxvii. (1900) V Abt., pp. 525-6 (1 fig.), 

 t Brit. Med. Journ., 1900, i. p. 1015. 



