Intravenous literature: Anon (2013) Sarstedt AG & Co.; Patent Issued for Blood-Drawing Device, in Particular for Infants and Small Children Or Small Animals. Journal of Engineering. January 2nd, p.2428.
The blood specimen can then be emptied directly into a specimen vessel from the open, possibly also curved, rear end of the needle. Since it is very problematic to hold a collection vessel below the open end of the needle to enable reliable collection of the blood specimen, one person holds the patient and performs the puncture operation while another person holds the specimen vessel for receiving the blood.