AGREEMENT OF LIMITED PARTNERSHIP

<PAGE>

EXHIBIT 3.4

AGREEMENT OF LIMITED PARTNERSHIP

OF

EMERGENCY MEDICAL SERVICES L.P.

This Agreement of Limited Partnership is entered into and shall be

effective as of February 10, 2005, by and among Emergency Medical Services

Corporation, a Delaware corporation as a general partner (the "GENERAL

PARTNER"), and the Persons listed on Schedule A attached hereto as limited

partners.

NOW, THEREFORE, in consideration of the premises, the parties do hereby

agree as follows:

1. CERTAIN DEFINITIONS. As used herein, the following terms shall have

the following respective meanings:

"ACT" means the Delaware Revised Uniform Limited Partnership Act.

"ADJUSTED CAPITAL ACCOUNT" means, with respect to any Partner such

Partner's Capital Account, increased for the amount such Partner is deemed

obligated to restore pursuant to (A) the penultimate sentences of Regulations

Section 1.704-2(g)(l) and 1.704-2(i)(5) and (B) Regulations Sections

1.704-1(b)(2)(ii)(c), as of the end of the Company's Fiscal Year or other

applicable period, and reduced for the items described in Regulations Sections

1.704-1(b)(2)(ii)(d)(4), (5) and (6).

"CAPITAL ACCOUNTS" has the meaning set forth in Section 4.2.

"CAPITAL CONTRIBUTIONS" means the money and property contributed by

the Partners to the Limited Partnership pursuant to the provisions of Section 3

of this Agreement.

"CERTIFICATE" means the Certificate of Limited Partnership of the

Partnership, as amended from time to time. Unless the context requires

otherwise, any reference to the "Certificate" shall be to the Certificate as the

same shall be in effect at the time to which such reference relates.

"CLASS A UNITS" means all Units of the Partnership other than Class

B Units.

"CLASS B UNITS" has the meaning given to that term in Section 4.4.

"CODE" means the Internal Revenue Code of 1986, as amended from time

to time, including the corresponding provisions of any successor law.

"COMPANY" means Emergency Medical Services L.P.

"DEPRECIATION" means, for each Fiscal Year or other period, an

amount equal to the depreciation, amortization or other cost recovery deduction

allowed or allowable for federal income tax purposes with respect to an asset

for such Fiscal Year; provided, however, that, except as otherwise provided in

Regulations Section 1.704-2, if the Gross Asset Value of an asset differs from

its adjusted basis for federal income tax purposes at the beginning of such

Fiscal Year or other period, Depreciation shall be an amount which bears the

same ratio to such beginning Gross Asset Value as the federal income tax

depreciation, amortization or other cost recovery deduction for such Fiscal Year

or other period bears to such beginning adjusted tax basis; provided, further,

that, if the adjusted basis for federal income tax purposes of an asset at the

beginning of such Fiscal Year or other period is zero, Depreciation shall be

determined with reference to such beginning Gross Asset Value using any

reasonable method selected by the General Partner; and provided further, that,

with respect to any asset to which the remedial allocation

<PAGE>

method is applied pursuant to Section 6.6, Depreciation with respect to such

asset shall be calculated in accordance with Regulations Section 1.704-3(d)(2).

"FISCAL YEAR" means (a) the period commencing on the date hereof and

ending on August 31, 2005 and (b) any subsequent 12-month period commencing on

January 1.

"GENERAL PARTNER" has the meaning given that term in the first

paragraph of this Agreement.

"GROSS ASSET VALUE" means, with respect to any asset of the

Partnership, such asset's adjusted basis for federal income tax purposes, except

as follows:

(a) the initial Gross Asset Value of any asset contributed by a

Partner to the Partnership shall be the gross fair market value of such

asset (computed without taking Section 7701(g) of the Code into account),

without reduction for liabilities, as determined by the contributing

Partner and the Partnership;

(b) if the General Partner reasonably determines that an adjustment

is necessary or appropriate to reflect the relative economic interests of

the Partners, the Gross Asset Values of all Partnership assets shall be

adjusted in accordance with Regulations Sections 1.704-1(b)(2)(iv)(f) and

(g) to equal their respective gross fair market values, without reduction

for liabilities, as reasonably determined by the General Partner, as of

the following times:

(i) a Capital Contribution (other than a de minimis Capital

Contribution) to the Partnership by a new or existing Partner as

consideration for Units; or

(ii) the distribution by the Partnership to a Partner of more

than a de minimis amount of Partnership assets as consideration for

the redemption of an interest in the Partnership; or

(iii) the liquidation of the Partnership within the meaning of

Regulations Section 1.704-1(b)(2)(ii)(g); or

(iv) the grant of more than a de minimis number of Units as

consideration for the provision of services to or for the benefit of

the Partnership;

(c) the Gross Asset Values of Partnership assets distributed to any

Partner shall be the gross fair market values of such assets (computed

without taking Section 7701(g) of the Code into account) without reduction

for liabilities, as reasonably determined by the General Partner as of the

date of distribution; and

(d) the Gross Asset Values of Partnership assets shall be increased

(or decreased) to reflect any adjustments to the adjusted basis of such

assets pursuant to Sections 734(b) or 743(b) of the Code, but only to the

extent that such adjustments are taken into account in determining Capital

Accounts pursuant to Section 1.704-1(b)(2)(iv)(m) of the Regulations;

provided, however, that Gross Asset Values shall not be adjusted pursuant

to this paragraph (iv) to the extent that the General Partner reasonably

determines that an adjustment pursuant to paragraph (ii) above is

necessary or appropriate in connection with a transaction that would

otherwise result in an adjustment pursuant to this paragraph (d).

At all times, Gross Asset Values shall be adjusted by any Depreciation taken

into account with respect to the Partnership's assets for purposes of computing

Net Profits and Net Losses.

"LIMITED PARTNERS" means (a) those Persons listed on Schedule A

attached hereto and (b) any transferee thereof or other Person admitted as a

limited partner pursuant to the terms of this Agreement.

-2-

<PAGE>

"NET PROFITS" AND "NET LOSSES" mean, for each Fiscal Year of the

Partnership or other applicable period, an amount equal to the Partnership's

taxable income or loss for such year or period, as determined for federal income

tax purposes, and computed in accordance with Section 703(a) of the Code (for

this purpose, all items of income, gain, loss or deduction required to be

separately stated pursuant to Section 703(a)(1) of the Code shall be included in

taxable income or loss) with the following adjustments:

(a) any income of the Partnership that is exempt from federal income

tax and not otherwise taken into account in computing Net Profits or Net

Losses pursuant to this definition shall be treated as an item of gross

income in determining taxable income or loss;

(b) in the event an adjustment to the Gross Asset Value of a

property which requires that the Capital Accounts be adjusted pursuant to

Regulations Sections 1.704-1(b)(2)(iv)(e), (f), (g) and (m), the amount of

such adjustment shall be taken into account as gain or loss from the

disposition of the property for purposes of computing Net Profits or Net

Losses;

(c) gain or loss resulting from the disposition of a property shall

be computed by reference to the Gross Asset Value of the property,

notwithstanding that the adjusted tax basis of the property differs from

its Gross Asset Value;

(d) in lieu of the depreciation, amortization and other cost

recovery deductions, there shall be taken into account Depreciation in

computing such taxable income or loss;

(e) to the extent an adjustment to the adjusted tax basis of any

Partnership asset pursuant to Code Section 734(b) or Code Section 743(b)

is required pursuant to Regulations Section 1.704-1(b)(2)(iv)(m)(4) to be

taken into account in determining Capital Accounts as a result of a

distribution other than in complete liquidation of a Partner's interest in

the Partnership, the amount of such adjustment shall be treated as an item

of gain (if the adjustment increases the basis of the asset) or loss (if

the adjustment decreases the basis of the asset) from the disposition of

the asset and shall be taken into account for purposes of computing Net

Profits or Net Losses;

(f) by treating as a deductible expense any expenditure of the

Partnership described in Section 705(a)(2)(B) of the Code (or which is

treated as a Section 705(a)(2)(B) expenditure pursuant to Regulations

Section 1.704-1(b)(2)(iv)(i)) and not otherwise taken into account in

computing Net Profits or Net Losses, including amounts paid or incurred to

organize the Partnership (unless an election is made pursuant to Section

709(b) of the Code) or to promote the sale of interests in the

Partnership) and by treating deductions for any losses incurred in

connection with the sale or exchange of Partnership property disallowed

pursuant to Section 267(a)(1) or 707(b) of the Code as expenditures

described in Section 705(a)(2)(B) of the Code; and

(g) notwithstanding any other provision of this definition, any

items which are specially allocated pursuant to Article 6 shall not be

taken into account in computing Net Profits or Net Losses.

"PARTNERS" shall mean the General Partner and the Limited Partners,

collectively, and "PARTNER" shall mean a General Partner or a Limited Partner

as the context shall require.

"PARTNERSHIP" means the limited partnership formed by the execution

of this Agreement and known as Emergency Medical Services L.P.

"PERCENTAGE INTERESTS" has the meaning set forth in Section 4.1.

"PERSON" means any natural person, corporation, partnership, joint

venture, trust, association or other business or legal entity.

-3-

<PAGE>

"REGULATIONS" means the Treasury Regulations promulgated under the

Code, as amended from time to time, including the corresponding provisions of

any successor regulations.

"UNITS" means the units of each Limited Partner representing such

Limited Partner's interest in the income, gains, losses, deductions and expenses

of the Partnership as set forth on Schedule A attached hereto, as amended from

time to time in accordance with the terms of this Agreement. Unless otherwise

indicated, a reference to Units shall be to both Class A Units and Class B

Units.

2. FORMATION, PURPOSE, TERM.

2.1 FORMATION. The parties hereby confirm the formation of the

Partnership under the name Emergency Medical Services L.P., in accordance with

the Act. Promptly upon execution and delivery of this Agreement, the General

Partner shall cause a restated Certificate, if required by the Act, to be filed

or recorded in all appropriate public offices.

2.2 PURPOSE; LIMITATIONS. The purpose of the Partnership is to

engage in any activities permitted under the Act, including, without limitation,

to own and invest in real estate and marketable securities.

2.3 PRINCIPAL OFFICE. The principal office of the Partnership shall

be located at such place as the General Partner may determine. The General

Partner shall give notice to the Limited Partners promptly of the location of

the principal office of the Partnership and of any change thereof.

2.4 REGISTERED AGENT. The registered agent of the Partnership in

Delaware shall be Corporation Service Company.

2.5 TERM. The Partnership commenced on the date of the filing of the

original Certificate of Limited Partnership with the office of the Secretary of

State of Delaware and shall terminate as herein provided.

3. CONTRIBUTIONS.

3.1 INITIAL CONTRIBUTIONS. On or prior to the date hereof, the

Partners have made the contributions to the Partnership set forth on Schedule A

attached hereto.

3.2 ADDITIONAL CONTRIBUTIONS. No Partner shall be required to make

any additional contributions to the capital of the Partnership. Nothing

contained in this Section 3.2 shall be deemed to limit the obligations of the

General Partner in respect of liabilities of the Partnership under this

Agreement or under the Act. With the consent of the General Partner, any Partner

may make an additional contribution to the Partnership.

4. PERCENTAGE INTERESTS; CAPITAL ACCOUNTS; UNITS.

4.1 PERCENTAGE INTERESTS. The Percentage Interest (a) of the General

Partner shall be 0.001 percent and (b) of each Limited Partner, the product of

(i) 0.999 and (ii) the percentage of outstanding Units owned by such Limited

Partner.

4.2 CAPITAL ACCOUNTS The Partnership shall determine and maintain a

"Capital Account" for each Partner throughout the full term of the Partnership

in accordance with the provisions of Regulations Section 1.704-1(b)(2)(iv), as

such regulation may be amended from time to time. Without limiting the

foregoing, the following provisions shall apply:

(a) The Capital Account of each Partner shall be increased by (i)

the amount of such Partner's cash contributions and the initial Gross

Asset Value of property contributed to the Partnership by such Partner

(net of liabilities securing such contributed property that the

-4-

<PAGE>

Partnership is considered to assume or take subject to under Section 752

of the Code), (ii) such Partner's share of the Partnership's Net Profits,

and (iii) the amount of any Partnership liabilities that are assumed by

such Partner other than liabilities described in Section 4.2(a)(i).

(b) The Capital Account of each Partner shall be decreased by (i)

the amount of cash distributions to such Partner and the Gross Asset Value

of property distributed to such Partner (net of liabilities assumed by

such Partner and liabilities to which such distributed property is

subject), (ii) such Partner's share of the Partnership's Net Losses, and

(iii) the amount of any liabilities of such Partner that are assumed by

the Partnership other than liabilities described in Section 4.2(b)(i).

(c) A Partner who has more than one interest in the Partnership

shall have a single Capital Account that reflects all of such interests,

regardless of the class of interests owned by such Partner (e.g., general

or limited) and regardless of the time or manner in which such interests

are acquired.

(d) Upon the transfer by a Partner of Units (i) if such transfer

does not cause a termination of the Partnership within the meaning of

Section 708(b)(1)(B) of the Code, the Capital Account of the transferor

Partner that is attributable to the transferred interest will be carried

over to the transferee Partner and, if the Partnership has a Section 754

election in effect, the Capital Account will not be adjusted to reflect

any adjustment under Section 743 of the Code; or (ii) if such transfer

causes a termination of the Partnership within the meaning of Code Section

708(b)(1)(B), the income tax consequences of such termination shall be

governed by the relevant provisions of Subchapter K of Chapter 1 of the

Code and the Regulations promulgated thereunder, and the initial Capital

Accounts of the Partners in the Partnership resulting from such

termination (which for all other purposes continues to be the Partnership)

shall be determined in accordance with Regulation Sections

1.704-1(b)(2)(iv)(d), (e), (f), (g) and (l) under Section 704(b) of the

Code and thereafter in accordance with this Section 4.2.

4.3 UNITS. The interests of the Limited Partners in the Partnership

shall be in the form of Units issued by the Partnership, which Units shall

represent an individual undivided interest in the rights of all Limited Partners

in capital, profits, losses and distributions of or from the Partnership. Unless

otherwise designated, all Units shall be Class A Units.

4.4 CLASS B UNITS. The General Partner is hereby authorized to issue

additional interests in the Partnership to employees, consultants, contractors

and other parties who perform services for or on behalf of the Partnership on

the terms and conditions set forth in this Section 4.4. The General Partner is

further authorized to issue to employees, consultants, contractors and other

parties who perform services for or on behalf of the Partnership options or

other rights to acquire such Units at some time in the future. The interests in

the Partnership issued pursuant to this Section 4.4 shall be designated as

"Class B Units."

(a) The Partnership shall designate the number of Class B Units

issued hereunder, and shall revise Schedule A attached hereto to reflect

the issuance of such Units, and the name and address of the holder

thereof. The aggregate Percentages Interests of all outstanding Class B

Units at any time shall not exceed 15 percent.

(b) Holders of the Class B Units shall not be entitled to any vote

on any matter requiring the vote of the Limited Partners hereunder.

(c) Except as expressly provided herein, Class B Units shall be

identical in their terms to Class A Units and each Class A Unit and Class

B Unit shall be entitled to equal shares of distribution and allocations

as provided herein.

-5-

<PAGE>

5. DISTRIBUTIONS.

5.1 DISTRIBUTIONS. Distributions by the Partnership to the Partners

shall be made at the times and in the aggregate amounts determined by the

General Partner in its sole and absolute discretion and shall be made to the

Partners in accordance with their respective Percentage Interests.

5.2 CAPITAL ACCOUNT LIMITATION; LIQUIDATION. Upon the liquidation of

the Partnership or of any Partner's interest in the Partnership (as both are

defined in Section 5.3), liquidation proceeds, if any, shall be distributed to

the extent of and in proportion to each Partner's positive Capital Account

balance within the meaning of Regulations Section 1.704-1(b)(2)(ii)(b), after

giving effect to all allocations to such Partner under Article 6, and the

allocation of deemed gain or loss described in clause (b) of the definition of

"Net Profits" and "Net Losses" set forth in Article 1.

5.3 CERTAIN DEFINITIONS. For purposes of this Agreement, (i) the

term "liquidation of the Partnership" shall mean either (a) a termination of the

Partnership, which shall be deemed to occur on the date upon which the

Partnership ceases to be a going concern and is continued in existence solely to

wind up its affairs, or (b) a termination of the Partnership pursuant to Section

708(b)(1) of the Code; and (ii) the term "liquidation of a Partner's interest in

the Partnership" shall mean the termination of the Partner's entire interest in

the Partnership effected by a distribution, or a series of distributions, by the

Partnership to the Partner in redemption or cancellation of such Partner's Units

or, in the case of the General Partner, interest in the Partnership.

6. ALLOCATIONS.

6.1 GENERAL ALLOCATIONS. Except as provided in Sections 6.2, 6.3 and

6.4, Net Profits, Net Losses and credits shall be allocated among the Partners

in accordance with their respective Percentage Interests.

6.2 ALLOCATIONS OF GAINS.

(a) Gain realized upon the sale or other disposition of property by

the Partnership, including deemed sales described in clause (b) of the

definition of "Net Profits" and "Net Losses" set forth in Article 1, shall

be allocated in the following order:

(b) There shall first be allocated to those Partners, if any, who

have deficit balances in their Capital Accounts immediately prior to such

sale or other disposition an amount of such gain equal to the aggregate

amount of such deficit balances, which amount shall be allocated in the

same proportion as such deficit balances.

(c) There shall next be allocated to each of the Partners gain in

such amounts and proportions as are necessary so that the positive Capital

Account balances of the Partners are in proportion to their respective

Percentage Interests.

(d) Any remaining gain shall be allocated among the Partners

accordance with their respective Percentage Interests.

(e) If the Partnership shall realize, upon a sale or other

disposition, gain which does not constitute long-term capital gain and to

which the provisions of Section 1231 of the Code do not apply, the

foregoing provisions of this Section 6.2 shall be successively applied to

(i) such gain, (ii) gain which is subject to the provisions of Section

1231 of the Code and (iii) long-term capital gain.

6.3 ALLOCATION OF LOSSES. Losses realized upon the sale or other

disposition of property by the Partnership, including deemed sales described in

clause (b) of the definition of "Net Profits" and "Net Losses" set forth in

Article 1, shall be allocated in the following order:

(a) There shall first be allocated to those Partners, if any, who

have positive Adjusted Capital Accounts balances an amount of such loss

necessary to reduce such positive Adjusted Capital Accounts balances to

zero.

-6-

<PAGE>

(b) The balance of such loss shall be allocated to the General

Partner.

6.4 SPECIAL ALLOCATIONS. Notwithstanding anything in this Agreement

to the contrary:

(a) All nonrecourse deductions (as defined in Regulations Section

1.704-2(b)(1)) shall be charged to the Capital Accounts of the Partners in

proportion to their respective Percentage Interests.

(b) No Partner shall be allocated any item of loss or deduction to

the extent said alloca