136 



t*' 



SUCTION PIPE 



GLfiSS TUBE CON- 

 TfllNINO- POLLEN IN 

 LIQUID METHACRYLATE. 



^ 



2 GELATINE CAPSULES 

 FILLED WITH METHA- 

 CRYLATE. 



GEL ATI ME CAPSULE 

 WITH COVERING LID 

 C ORDINARY SIZE) 



-> CARDBOARD HOLD- 

 ER IN WHICH THE 

 GELATINE CAPSU- 

 LES ARE PLACED 

 READY FOR 

 FILL/NO. 



Fig. 254. Outfit for filling the gelatine capsules. 



15 cm. At the Palynoloi^ical Laboratory, Bromma, the gelatine capsules 

 are usually exposed to UV radiation during five nights, approximating 15 

 hours per night. During the first night, before the hardening of the plastic, 

 the heat from the UV lamp should be checked by a ventilator in order to 

 avoid the formation of air-bubbles in the sediment at the bottom of the 

 capsules before the methacrylate solidifies (Fig. 255). After about 80 hours 

 of exposition to the UV lamp the plastic is, as a rule, sufficiently hard for 



cutting. 



Cutting is rendered difficult if there are air-buijbles in the methacrylate. 

 The bubbles may be due to various causes, for instance, as already men- 



