EXHIBIT 10.1

FIRST LOAN MODIFICATION AGREEMENT

This First Loan Modification Agreement (this “Loan Modification Agreement”) is entered into as of February 26, 2007, by and between SILICON VALLEY BANK, a California corporation, with its principal place of business at 3003 Tasman Drive, Santa Clara, California 95054 and with a loan production office located at One Newton Executive Park, Suite 200, 2221 Washington Street, Newton, Massachusetts 02462 (“Bank”) and CALIPER LIFE SCIENCES, INC., a Delaware corporation (“Caliper”), NOVASCREEN BIOSCIENCES CORPORATION, a Delaware corporation (“Novascreen”), XENOGEN CORPORATION, a Delaware corporation (“Xenogen”), and XENOGEN BIOSCIENCES CORPORATION, an Ohio corporation (“Xenogen Biosciences”), each with its chief executive office at 68 Elm Street, Hopkinton, Massachusetts 01748 (jointly, severally, individually and collectively, “Borrower”).

1.             DESCRIPTION OF EXISTING INDEBTEDNESS AND OBLIGATIONS. Among other indebtedness and obligations which may be owing by Borrower to Bank, Borrower is indebted to Bank pursuant to a loan arrangement dated as of August 9, 2006, evidenced by, among other documents, a certain Loan and Security Agreement dated as of August 9, 2006, among Caliper, Novascreen and Bank, as amended by that certain Joinder Agreement dated as of September 28, 2006, between Borrower and Bank, which, among other things, added Xenogen and Xenogen Biosciences as co-borrowers under the Loan and Security Agreement (as amended, the “Loan Agreement”).  Capitalized terms used but not otherwise defined herein shall have the same meaning as in the Loan Agreement.

2.             DESCRIPTION OF COLLATERAL.  Repayment of the Obligations is secured by the Collateral as described in the Loan Agreement (together with any other collateral security granted to Bank, the “Security Documents”).  Hereinafter, the Security Documents, together with all other documents evidencing or securing the Obligations shall be referred to as the “Existing Loan Documents”.

3.             DESCRIPTION OF CHANGE IN TERMS.

A.                                   Modifications to Loan Agreement.

1.                                       The Loan Agreement shall be amended by deleting the following text appearing in Section 2.3 thereof, entitled “Payment of Interest on Credit Extensions”:

“(a)         Interest Rate.  Subject to Section 2.3(b), the principal amount outstanding under the Revolving Line shall accrue interest at a floating per annum rate equal to: (x) if Borrower’s Unrestricted Cash is equal to or greater than Twenty Million Dollars ($20,000,000.00), the Prime Rate, or (y) if Borrower’ Unrestricted Cash is less than Twenty Million Dollars ($20,000,000.00), one-half of one percentage point (.50%) above the Prime Rate, which interest shall be payable monthly in accordance with Section 2.3(f) below.   Any changes to the applicable interest rate due as set forth in (x) or (y) above, shall be effective on the first day of the month following such event.”

and inserting in lieu thereof the following:

“(a)         Interest Rate.  Subject to Section 2.3(b), the principal amount outstanding under the Revolving Line shall accrue interest at a floating per annum rate equal to: (x) if Borrower’s Unrestricted Cash is equal to or greater than Twenty Million Dollars ($20,000,000.00), the Prime Rate, or (y) if Borrower’s Unrestricted Cash is less than Twenty Million Dollars ($20,000,000.00), one-half of one percentage point (0.50%) above the Prime Rate, which interest shall be payable monthly in accordance with Section 2.3(f)

below.  Any changes to the applicable interest rate due as set forth in (x) or (y) above, shall be effective on the first day of the month following such event. Notwithstanding the foregoing, during the month ending January 31, 2007, the principal amount outstanding under the Revolving Line shall accrue interest at a floating per annum rate equal to the Prime Rate, which interest shall be payable monthly in accordance with Section 2.3(f) below.”

2.                                       The Loan Agreement shall be amended by deleting the following text appearing in Section 6.2 thereof, entitled “Financial Statements, Reports, Certificates”:

“(b)         Within thirty (30) days after the last day of each month in which the Borrower’s Unrestricted Cash is less than Twenty Million Dollars ($20,000,000.00), and Advances are outstanding or an Advance request has been made, deliver to Bank a duly completed Borrowing Base Certificate signed by a Responsible Officer, with aged listings of accounts receivable (by invoice date).”

and inserting in lieu thereof the following:

“(b)         Within thirty (30) days after the last day of each month (except for the month ending December 31, 2006) in which the Borrower’s Unrestricted Cash is less than Twenty Million Dollars ($20,000,000.00), and Advances are outstanding or an Advance request has been made, deliver to Bank a duly completed Borrowing Base Certificate signed by a Responsible Officer, with aged listings of accounts receivable (by invoice date).”

3.                                       The Loan Agreement shall be amended by deleting the following Section 6.7 thereof, entitled “Financial Covenants”:

“6.7        Financial Covenants.

Borrower shall maintain at all times, to be tested as of the last day of each quarter:

(a)           Adjusted Quick Ratio.  A ratio of Quick Assets to Quick Liabilities of at least 1.25 to 1.0; and

(b)           Minimum EBITDA-Cap Ex.  Borrower’s EBITDA minus its capital expenditures, (“EBITDA-Cap Ex”) for the two (2) quarter period ending with each quarter, shall be in an amount equal to: (i) losses not greater than (x) Seven Million Dollars ($7,000,000.00) for the quarter ending September 30, 2006; (y) Six Million Dollars ($6,000,000.00) for the quarters ending December 31, 2006, March 31, 2007, and June 30, 2007; and (z) Three Million Dollars ($3,000,000.00) for the quarter ending September 30, 2007; and (ii) at least Zero Dollars ($0.00) for the quarter ending December 31, 2007, and as of the last day of each quarter thereafter.”

and inserting in lieu thereof the following:

“6.7        Financial Covenants.

Borrower shall maintain at all times, to be tested as of the last day of each quarter:

(a)           Adjusted Quick Ratio.  (i) prior to and including the quarter ended, December 31, 2006, a ratio of Quick Assets to Quick Liabilities of at least 1.25 to 1.0; and (ii) commencing with the quarter ending March 31, 2007, a ratio of Quick Assets to Quick Liabilities of at least 1.10 to 1.0; and

(b)           Minimum EBITDA-Cap Ex.  Borrower’s EBITDA minus its capital expenditures, (“EBITDA-Cap Ex”) for the two (2) quarter period ending with each quarter, shall be in an amount equal to: (i) losses not greater than (A) Seven Million Dollars ($7,000,000.00) for the quarter ending September 30, 2006; (B) Eight Million Dollars ($8,000,000.00) for the quarter ending December 31, 2006; (C) Eight Million Dollars ($8,000,000.00) for the quarter ending March 31, 2007, (D) Seven Million Dollars ($7,000,000.00) for the quarter ending June 30, 2007; and (E) Four Million Dollars ($4,000,000.00) for the quarter ending September 30, 2007; and (ii) at least Zero Dollars ($0.00) for the quarter ending December 31, 2007, and as of the last day of each quarter thereafter.”

4.                                       The Loan Agreement shall be amended by deleting the following definition appearing in Section 13.1 thereof:

““Quick Assets” is, on any date, all cash and Cash Equivalents and Marketable Securities as shown on Borrower’s consolidated financial statements as of such date prepared in accordance with GAAP, plus net billed accounts receivable, excluding any cash or Cash Equivalents and Marketable Securities that are restricted or are pledged to any Person other than Bank or any of Bank’s Affiliates.”

and inserting in lieu thereof the following:

““Quick Assets” is, on any date, all cash and Cash Equivalents and Marketable Securities as shown on Borrower’s consolidated financial statements as of such date prepared in accordance with GAAP, plus net billed accounts receivable and Unbilled Accounts, excluding any cash or Cash Equivalents and Marketable Securities that are restricted or are pledged to any Person other than Bank or any of Bank’s Affiliates.”

5.                                       The Loan Agreement shall be amended by inserting the following definition, in alphabetical order, in Section 13.1 thereof:

““Unbilled Account” is the estimated face value amount (as reasonably determined by Borrower based upon the best information available to Borrower) of an invoice for an Account pursuant to services performed by Borrower, which invoice will be generated (but has not yet been generated) within thirty (30) days of the last day of the month in which such services were performed, net of any offsets.”

6.                                       The Compliance Certificate appearing as Exhibit D to the Loan Agreement is hereby replaced with the Compliance Certificate attached as Exhibit A hereto.

4.             FEES.  Borrower shall pay to Bank a modification fee equal to $20,000.00, which fee shall be due on the date hereof and shall be deemed fully earned as of the date hereof.  Borrower shall also reimburse Bank for all legal fees and expenses incurred in connection with this amendment to the Existing Loan Documents.

5.             RATIFICATION OF PERFECTION CERTIFICATE.  Borrower hereby ratifies, confirms and reaffirms, all and singular, the terms and disclosures contained in a certain Perfection Certificate dated as of October 25, 2006

between Borrower and Bank, and acknowledges, confirms and agrees the disclosures and information above Borrower provided to Bank in the Perfection Certificate has not changed, as of the date hereof.

6.             AUTHORIZATION TO FILE.  Borrower hereby authorizes Bank to file UCC financing statements without notice to Borrower, with all appropriate jurisdictions, as Bank deems appropriate, in order to further perfect or protect Bank’s interest in the Collateral, including a notice that any disposition of the Collateral, by either the Borrower or any other Person, shall be deemed to violate the rights of the Bank under the Code.

7.             CONSISTENT CHANGES.  The Existing Loan Documents are hereby amended wherever necessary to reflect the changes described above.

8.             RATIFICATION OF LOAN DOCUMENTS.  Borrower hereby ratifies, confirms, and reaffirms all terms and conditions of all security or other collateral granted to the Bank, and confirms that the indebtedness secured thereby includes, without limitation, the Obligations.

9.             NO DEFENSES OF BORROWER.  Borrower hereby acknowledges and agrees that Borrower has no offsets, defenses, claims, or counterclaims against Bank with respect to the Obligations, or otherwise, and that if Borrower now has, or ever did have, any offsets, defenses, claims, or counterclaims against Bank, whether known or unknown, at law or in equity, all of them are hereby expressly WAIVED and Borrower hereby RELEASES Bank from any liability thereunder.

10.           CONTINUING VALIDITY.  Borrower understands and agrees that in modifying the existing Obligations, Bank is relying upon Borrower’s representations, warranties, and agreements, as set forth in the Existing Loan Documents.  Except as expressly modified pursuant to this Loan Modification Agreement, the terms of the Existing Loan Documents remain unchanged and in full force and effect.  Bank’s agreement to modifications to the existing Obligations pursuant to this  Loan Modification Agreement in no way shall obligate Bank to make any future modifications to the Obligations.  Nothing in this Loan Modification Agreement shall constitute a satisfaction of the Obligations.  It is the intention of Bank and Borrower to retain as liable parties all makers of Existing Loan Documents, unless the party is expressly released by Bank in writing.  No maker will be released by virtue of this Loan Modification Agreement.

11.           JURISDICTION/VENUE.  Borrower accepts for itself and in connection with its properties, unconditionally, the exclusive jurisdiction of any state or federal court of competent jurisdiction in the Commonwealth of Massachusetts in any action, suit, or proceeding of any kind against it which arises out of or by reason of this Loan Modification Agreement; provided, however, that if for any reason Bank cannot avail itself of the courts of the Commonwealth of Massachusetts, then venue shall lie in Santa Clara County, California.  NOTWITHSTANDING THE FOREGOING,  THE BANK SHALL HAVE THE RIGHT TO BRING ANY ACTION OR PROCEEDING AGAINST THE BORROWER OR ITS PROPERTY IN THE COURTS OF ANY OTHER JURISDICTION WHICH THE BANK DEEMS NECESSARY OR APPROPRIATE IN ORDER TO REALIZE ON THE COLLATERAL OR TO OTHERWISE ENFORCE THE BANK’S RIGHTS AGAINST THE BORROWER OR ITS PROPERTY.

12.           COUNTERSIGNATURE.  This Loan Modification Agreement shall become effective only when it shall have been executed by Borrower and Bank.

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This Loan Modification Agreement is executed as a sealed instrument under the laws of the Commonwealth of Massachusetts as of the date first written above.

EXHIBIT A
COMPLIANCE CERTIFICATE

The undersigned authorized officers of Caliper Life Sciences, Inc., NovaScreen Biosciences Corporation, XenogenCorporation, and Xenogen Biosciences Corporation (individually and collectively, “Borrower”) certify that under the terms and conditions of the Loan and Security Agreement between Borrower and Bank (the “Agreement”), (1) Borrower is in complete compliance for the period ending _______________ with all required covenants except as noted below, (2) there are no Events of Default, (3) all representations and warranties in the Agreement are true and correct in all material respects on this date except as noted below; provided, however, that such materiality qualifier shall not be applicable to any representations and warranties that already are qualified or modified by materiality in the text thereof; and provided, further that those representations and warranties expressly referring to a specific date shall be true, accurate and complete in all material respects as of such date, (4) Borrower, and each of its Subsidiaries, has timely filed all required tax returns and reports, and Borrower has timely paid all foreign, federal, state and local taxes, assessments, deposits and contributions owed by Borrower except as otherwise permitted pursuant to the terms of Section 5.9 of the Agreement, and (5) no Liens have been levied or claims made against Borrower relating to unpaid employee payroll or benefits of which Borrower has not previously provided written notification to Bank.  Attached are the required documents supporting the certification.  The undersigned certifies that these are prepared in accordance with GAAP consistently applied from one period to the next except as explained in an accompanying letter or footnotes.  The undersigned acknowledges that no borrowings may be requested at any time or date of determination that Borrower is not in compliance with any of the terms of the Agreement, and that compliance is determined not just at the date this certificate is delivered.  Capitalized terms used but not otherwise defined herein shall have the meanings given them in the Agreement.

Please indicate compliance status by circling Yes/No under “Complies” column.

*                    As set forth in Section 6.7(b) of the Agreement.

The following financial covenant analyses and information set forth in Schedule 1 attached hereto are true and accurate as of the date of this Certificate.

The following are the exceptions with respect to the certification above:  (If no exceptions exist, state “No exceptions to note.”)

Schedule 1 to Compliance Certificate

Financial Covenants of Borrower

Dated:    ____________________

In the event of a conflict between this Schedule and the Loan Agreement, the terms of the Loan Agreement shall control.

I.              ADJUSTED QUICK RATIO

Through 12/31/06, is line G equal to or greater than 1.25:1:00?
Thereafter, is line G equal to or greater than 1.10:1:00?

II.            MINIMUM EBITDA minus CAP-EX

Required: