September 27, 2018

Ben Silbert
General Counsel and Secretary
Avista Healthcare Public Acquisition Corp.
65 East 55th Street
18th Floor
New York, NY 10022

       Re: Avista Healthcare Public Acquisition Corp.
           Registration Statement on Form S-4
           Filed August 29, 2018
           File No. 333-227090

Dear Mr. Silbert:

       We have reviewed your registration statement and have the following
comments. In
some of our comments, we may ask you to provide us with information so we may
better
understand your disclosure.

       Please respond to this letter by amending your registration statement
and providing the
requested information. If you do not believe our comments apply to your facts
and
circumstances or do not believe an amendment is appropriate, please tell us why
in your
response.

       After reviewing any amendment to your registration statement and the
information you
provide in response to these comments, we may have additional comments.

Registration Statement on Form S-4 filed on August 29, 2018

Cover page

1.     Please revise your cover page to state the number of shares of Avista
Healthcare Public
       Acquisition Corp. (AHPAC) Class A common stock being exchanged in the
       domestication. Please also separately state the number of warrants being
issued pursuant
       to the domestication and merger. Refer to Item 501(b) of Regulation S-K.
2.     Please expand your disclosure to include the exchange ratio.

Following the business combination, with AHPAC's securities continue to trade
on a stock
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FirstName LastNameBen Acquisition Corp.
Avista Healthcare Public Silbert
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exchange ?, page 7

3.       We note your disclosure on page 72 that there can be no assurance that
ORGO common
         stock will be approved for listing on Nasdaq. Please revise your
disclosure on page 7 to
         clarify, if true, that the condition to obtain Nasdaq listing approval
under the merger
         agreement may be waived by the AHPAC board of directors.
Questions and Answers About the Proposals for AHPAC Shareholders
What happens if I vote against the Business Combination, page 9

4.       Please clarify any differences in expected cash payments between a
redemption following
         the business combination and cash payments if you are unable to
complete a business
         combination and are required to dissolve and liquidate. Specifically,
clarify whether there
         are any differences in the shareholders who are eligible to receive
the cash payments and
         whether amounts in the trust can be used to pay business expenses.
Summary Term Sheet, page 20

5.       We note that concurrently with the signing of the merger agreement,
the PIPE Investors
         subscribed for shares of Organogenesis, Inc. and that you entered into
a subscription
         agreement with the PIPE Investors for the purchase of shares of AHPAC
Class A common
         stock and warrants immediately following the domestication. Please
expand your
         disclosure to state the per share purchase price in each of these
transactions.
6.       We note your disclosure that AHPAC's public shareholders are expected
to retain no
         ownership in ORGO. We note also your statement on page 79 that
following the
         consummation of the business combination. ORGO will have no
significant assets other
         than its ownership interest in Organogenesis. Please tell us why you
believe it is
         appropriate to assume that 100% of AHPAC's public shareholders will
elect to redeem
         their shares. We may have further comment.
Related Agreements, page 25

7.       Please revise to describe the nature of each of the related
agreements, rather than
         providing only cross references to other sections of your document and
the actual
         agreement. The later description of these agreements, beginning on
page 139, should
         provide all the material terms of the agreements.
Conditions to Closing of the Business Combination, page 32

8.       Identify each condition that is subject to being waived.
Summary of the Consent Solicitation/Proxy Statement/Prospectus
Risk Factors, page 35

9.       Please expand your disclosure to highlight the following risks:
 Ben Silbert
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             the regulatory uncertainty as whether you will be required to
secure premarket
             clearance or premarket approval for certain of your products from
the U.S. Food and
             Drug Administration, as discussed on pages 50 to 51, including
that additional post-
             marketing requirements would also apply; and
             certain of the existing stockholders of Organogenesis have entered
into a controlling
             stockholders' agreement and are expected to control a majority of
the voting power of
             ORGO's outstanding Class A common stock after the completion of
the business
             combination, as discussed on page 79.
Risk Factors
Risks Related to AHPAC and the Business Combination, page 70

10.      Please add a risk factor discussing the exclusive forum provision that
is the subject of
         Proposal 7, including the risk that such a provision may limit a
shareholder's ability to
         bring a claim in a judicial forum that it finds favorable for such
disputes and may
         discourage lawsuits with respect to such claims. Additionally, please
add a risk factor
         discussing the conflicts of interest that may arise under the charter
provision concerning
         competitive businesses and corporate opportunities that is the subject
of Proposal 8.
The Business Combination
Background of the business combination, page 103

11.      We note your disclosure that AHPAC's management and the sponsor
conducted an
         analysis of over 30 acquisition targets, engaged in discussions or
additional due diligence
         with seventeen businesses and entered into non-disclosure agreements
with thirteen
         potential targets. We also note that the previous S-4 you filed
related to your merger
         agreement with Envigo indicated that you engaged in discussions or
additional due
         diligence with eight target businesses and entered into non-disclosure
agreements with
         five of them. Please explain the inconsistency.
12.      We note your disclosure that Organogenesis, AHPAC, Credit Suisse and
Wells Fargo
         drafted a private placement memo and held discussions with 14
potential investors during
         the time period beginning on June 21. According to disclosure on page
3 of your
         registration statement the "PIPE Investors" are Avista Capital
Partners IV, L.P. and Avista
         Capital Partners IV(Offshore). Please revise your discussion to
clarify when it was
         determined that your affiliates would purchase the shares in the
private placement.
         Additionally, identify the members of the PIPE Investors Investment
Committee.
13.      We note your disclosure on pages 103 to 109 regarding various
discussions with
         Organogenesis regarding transaction terms. Please expand your
disclosure to include the
         material developments in such discussions with respect to the
determination of the
         exchange ratio.
14.      We note your disclosure that on February 14, 2018 AHPAC and Envigo
mutually agreed
 Ben Silbert
FirstName LastNameBen Acquisition Corp.
Avista Healthcare Public Silbert
Comapany 27, 2018
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         to terminate the transaction agreement. Please expand your disclosure
to state the reasons
         for the termination.
15.      We note your disclosure that AHPAC actively negotiated definitive
documentation with
         three parties. Please expand your disclosure to describe the nature of
the business of the
         party with whom you conducted negotiations (other than Envigo), or
tell us why you
         believe such disclosure is not required. Please also explain why
negotiations with such
         party did not result in a definitive agreement.
16.      Please clarify whether the redemption rights and your assumption that
all public
         shareholders would exercise their redemption rights were discussed.
The AHPAC's Board's Reasons for the Approval of the Business Combination, page
109

17.      We note your disclosure that AHPAC conducted a valuation analysis in
order for the
         board of directors to ascertain the reasonableness of the merger
consideration. Please
         expand your disclosure to describe the analyses performed, including
comparables
         selected for evaluation, the Organogenesis valuation reviewed as part
of the due diligence
         review, the assumptions underlying such analyses and the resulting
valuation or valuation
         range resulting from the analyses.
Pro Forma Condensed Combined Balance Sheet as of June 30, 2018, page 153

18.      Tell us in greater detail how you computed the amounts for adjustment
(7) under each
         scenario 1 and scenario 2. In your pro forma condensed combined
balance sheet that
         assumes full redemption of AHPAC's Class A ordinary shares, you appear
to record the
         redemption amount in excess of the balance of "Class A ordinary shares
subject to
         possible redemption" against Additional paid-in capital. Please tell
us how you
         determined this was appropriate and why you did not record the excess
amount to
         accumulated deficit.
Information About Organogenesis
Clincial Trial Results
Renu, page 202

19.      We note your disclosure that interim results of the randomized control
trial show ReNu
         resulted in "statistically greater" improvements from baseline for
overall pain and pain,
         symptoms and activities of daily life. Please revise your disclosure
to discuss the interim
         results observed in terms of objective data points and explain whether
the results observed
         were statistically significant.
Intellectual Property, page 209

20.      We note your disclosure concerning your exclusive license agreement
with RESORBA
         Medical GmbH. Please expand your disclosure to include the royalty
rate, or royalty range
         not to exceed ten percent, on net sales of PuraPly AM, as well as the
term and termination
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Avista Healthcare Public Acquisition Corp.
September 27, 2018
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         provisions. Additionally, please file the license agreement as an
exhibit to the registration
         statement or tell us why you believe such filing is not required.
Beneficial Ownership of Securities, page 282

21.      Please expand your disclosure in footnote 8 to include the information
required by Item
         403 of Regulation S-K, including the natural person or persons who
have ultimate voting
         or investment control over the shares held by Avista Capital Partners
IV, LP and Avista
         Capital Partners IV (Offshore) LP.
Proposal 7: Exclusive Forum , page 296

22.      We note that your forum selection provision identifies the Court of
Chancery of the State
         of Delaware as the exclusive forum for certain litigation, including
any "derivative
         action." Please disclose whether this provision applies to actions
arising under the federal
         securities laws. Also ensure that the exclusive forum provision in
your proposed
         organizational documents states this clearly. In this regard, we note
that Section 27 of the
         Exchange Act creates exclusive federal jurisdiction over all suits
brought to enforce any
         duty or liability created by the Exchange Act or the rules and
regulations thereunder.
        We remind you that the company and its management are responsible for
the accuracy
and adequacy of their disclosures, notwithstanding any review, comments, action
or absence of
action by the staff.

       Refer to Rules 460 and 461 regarding requests for acceleration. Please
allow adequate
time for us to review any amendment prior to the requested effective date of
the registration
statement.

       You may contact Keira Nakada at 202-551-3659 or Kevin Vaughn at
202-551-3494 if
you have questions regarding comments on the financial statements and related
matters. Please
contact Christine Westbrook at 202-551-5019 or Suzanne Hayes at 202-551-3675
with any other
questions.



FirstName LastNameBen Silbert                         Sincerely,
Comapany NameAvista Healthcare Public Acquisition Corp.
                                                      Division of Corporation
Finance
September 27, 2018 Page 5                             Office of Healthcare &
Insurance
FirstName LastName