1900] MICROSCOPICAL JOURNAL. 293 



known. The authors have also devised a pipette for draw- 

 ing the required amount of blood. This consists of a grad- 

 uated glass tube to the upper end of which is attached a 

 short rubber tube. A special clamp, consisting of two lit- 

 tle metallic wheels between which the rubber is compress- 

 ed is placed on the latter at a short distance from the end 

 of the glass pipette. By turning the wheels with the 

 thumb the rubber tube is elongated and the blood enters 

 the capillary tube. It is best not to blow out the entire 

 quantity of blood iu the pipette, because if this is done 

 some air will get into the drop on the cover-glass and pre- 

 vent the successful counting. The amount of blood that 

 remains in the capillary tube is to be subtracted from the 

 amount first drawn into the pipette. Care must be taken 

 that the film of dry blood is thin and evenly spread over 

 both cover-glasses. The writers assert that they could 

 count from one to two thousand more white cells by this 

 method than the same specimens of blood showed by the 

 old method in the Thoma-Zeiss cell. The dilutent in that 

 method they say changes some white cells, and some of 

 them perish in the process of preparing the blood for 

 counting. These disadvantages are absent in dry speci- 

 mens; for even if some of the cells are destroyed in the 

 preparation of the specimen, they leave shadows upon 

 the slide that can easily be recognized. The new method 

 has also the advantage of allowing the operator to work 

 without haste, and the results of an examination can be 

 verified by a recount at at any time. — Drug Circular. 



Wanted. — Earth containg diatoms from Redondo Beach 

 for a European subscriber who offers cash, or, in exchange, 

 Hungarian diatomaceous material from St. Peter. C. W. S. 



Wanted. — Microscopic preparations illustrating the his- 

 tology of petals and sepals. Would like to get a full set for 

 John H. Lowell, Waldoboro, Maine. 



