Abstract: An injection apparatus for injecting and/or removing substances from subjects, such as avian eggs, includes an injection needle having a body portion and a tapered portion that terminates at a tip. A tube is attached to and extends around the injection needle in substantially concentric relationship therewith. The tube has an end portion positioned a predetermined distance from the needle tip. The tube end portion acts as a stop to limit the distance the needle tip can be inserted into a subject, such as an egg, through a membrane of the subject. A detector may be utilized to measure force exerted on a membrane of an egg by a stop attached to a needle. Force exerted on a membrane by a needle and/or by a needle and a stop attached to the needle may also be measured.

Abstract: Methods an apparatus for accurately and reliably positioning a device within an egg are provided. An opening is formed within a portion of the shell of an egg and a device is extended through the opening. The device includes a needle having a lumen containing a fluid under pressure. Fluid pressure is monitored and, in response to detecting a change in pressure of the fluid, movement of the device is stopped. Alternatively, fluid flow is monitored and, in response to detecting fluid flow from the needle, movement of the device is stopped. The device may be a substance delivery device that is configured to deliver a substance into the subgerminal cavity of the egg. The device may be a substance removal device that is configured remove a substance from an egg.

Abstract: An injection apparatus for injecting and/or removing substances from subjects, such as avian eggs, includes an injection needle having a body portion and a tapered portion that terminates at a tip. A tube is attached to and extends around the injection needle in substantially concentric relationship therewith. The tube has an end portion positioned a predetermined distance from the needle tip. The tube end portion acts as a stop to limit the distance the needle tip can be inserted into a subject, such as an egg, through a membrane of the subject. A detector may be utilized to measure force exerted on a membrane of an egg by a stop attached to a needle. Force exerted on a membrane by a needle and/or by a needle and a stop attached to the needle may also be measured.